PHYSICAL ELECTRONICS(ECE3540) CHAPTER 9 METAL SEMICONDUCTOR AND SEMICONDUCTOR HETERO-JUNCTIONS

Size: px
Start display at page:

Download "PHYSICAL ELECTRONICS(ECE3540) CHAPTER 9 METAL SEMICONDUCTOR AND SEMICONDUCTOR HETERO-JUNCTIONS"

Transcription

1 PHYSICAL ELECTRONICS(ECE3540) CHAPTER 9 METAL SEMICONDUCTOR AND SEMICONDUCTOR HETERO-JUNCTIONS Tennessee Technological University Wednesday, October 30, 013 1

2 Introduction Chapter 4: we considered the semiconductor in equilibrium and determined electron and hole concentrations in the conduction and valence bands, respectively. The net flow of the electrons and holes in a semiconductor generates current. The process by which these charged particles move is called transport. Chapter 5: we considered the two basic transport mechanisms in a semiconductor crystal: drift: the movement of charge due to electric fields, and diffusion: the flow of charge due to density gradients. Tennessee Technological University Wednesday, October 30, 013

3 Introduction Chapter 6: we discussed the behavior of nonequilibrium electron and hole concentrations as functions of time and space. We developed the ambi-polar transport equation which describes the behavior of the excess electrons and holes. Chapter 7: We considered the situation in which a p-type and an n-type semiconductor are brought into contact with one another to form a PN junction. Tennessee Technological University Wednesday, October 30, 013 3

4 Introduction Chapter 8: We considered the PN junction with a forward-bias applied voltage and determined the current-voltage characteristics. When holes flow from the p region across the space charge region into the n region, they become excess minority carrier holes and are subject to excess minority carrier diffusion, drift, and recombination. When electrons from the n region flow across the space charge region into the p region, they become excess minority carrier electrons and are subject to these same processes. Tennessee Technological University Wednesday, October 30, 013 4

5 Introduction When a sufficiently large reverse-bias voltage is applied across a PN junction, breakdown can occur, producing a large reverse-bias current in the junction, which can cause heating effects and catastrophic failure of the diode. Zener diodes are designed to operate in the breakdown region. Breakdown puts limits on the amount of voltage that can be applied across a PN junction. Tennessee Technological University Wednesday, October 30, 013 5

6 Introduction Chapter 9: we will consider the metalsemiconductor junction and the semiconductor hetero-junction, in which the material on each side of thejunctionisnotthesame.thesejunctionscan also produce diodes. An Ohmic contact is a low-resistance junction providing current conduction in both directions. We will examine the conditions that yield metalsemiconductor Ohmic contacts. Tennessee Technological University Wednesday, October 30, 013 6

7 Metal-Semiconductor Junction There are two kinds of metal-semiconductor contacts: Rectifying Schottky diodes: metal on lightly doped Silicon. Low-resistance Ohmic contacts: metal on heavily doped Silicon. Tennessee Technological University Wednesday, October 30, 013 7

8 The Schottky Barrier Diode Rectifying contacts are mostly made of n-type semiconductors; for this reason we will concentrate on this type of diode. In the ideal energy-band diagram for a particular metal and n- type semiconductor, the vacuum level is used as a reference. The parameter M is the metal work function (in volts), s is the semiconductor work function, and is known as the electron affinity. Before contact, the Fermi level in the semiconductor was above that in the metal. In order for the Fermi level to become a constant through the system in thermal equilibrium, electrons from the semiconductor flow into the lower energy states in the metal. Tennessee Technological University Wednesday, October 30, 013 8

9 The Schottky Barrier Diode The parameter B0 is the ideal barrier height of the semiconductor contact, the potential barrier seen by electrons in the metal trying to move into the semiconductor. The barrier is known as the Schottky barrier and is given as: 0 ( B M ) On the semiconductor side, is the built-in potential barrier. This barrier, similar to the case of the PN Junction, is the barrier seen by electrons in the conduction band trying to move into the metal V bi is given as: Vbi ( 0 n) B Tennessee Technological University Wednesday, October 30, 013 9

10 The Schottky Barrier Diode Bn Increases with Increasing Metal Work Function Vacuum level, E 0 q M Si = 4.05 ev M : Work Function of metal q Bn E c Si : Electron Affinity of Si E f Theoretically, Bn = M Si E v x = 0 x = x n Fig. 9.1: Ideal energy-band diagram of a metal-semiconductor junction Tennessee Technological University Wednesday, October 30,

11 The Schottky Barrier Diode Metal Depletion layer Neutral region q Bn N-Si E c E f Schottky barrier height, B, is a function of the metal material. E v P-Si E c E f B is the most important parameter. The sum of q Bn and q Bp is equal to E g. q Bp E v Fig. 9.: Energy Band Diagram of Schottky Contact Tennessee Technological University Wednesday, October 30,

12 The Schottky Barrier Diode Schottky barrier heights for electrons and holes Metal Mg Ti Cr W Mo Pd Au Pt Bn (V) Bp (V) Work Function m (V) Bn + Bp E g Bn increases with increasing metal work function Tennessee Technological University Wednesday, October 30, 013 1

13 The Schottky Barrier Diode q M q Bn Si = 4.05 ev + Vacuum level, E 0 Ec E f A high density of energy states in the band gap at the metal-semiconductor interface pins E f to a narrow range and Bn is typically 0.4 to 0.9 V Question: What is the typical range of Bp? E v Fig. 9.3: Fermi Level Pinning Tennessee Technological University Wednesday, October 30,

14 The Schottky Barrier Diode Schottky Contacts of Metal Silicide on Si Silicide: A Silicon and metal compound. It is conductive similar to a metal. Silicide-Si interfaces are more stable than metal-silicon interfaces. After metal is deposited on Si, an annealing step is applied to form a Silicide-Si contact. The term metal-silicon contact includes and almost always means Silicide-Si contacts. Silicide ErSi 1.7 HfSi MoSi ZrSi TiSi CoSi WSi NiSi Pd Si PtSi f Bn (V) f Bp (V) Table. 9.1: Schottky Contacts of Metal Silicide on Si Tennessee Technological University Wednesday, October 30,

15 The Schottky Barrier Diode q q Bn bi q Bn q( bi + V) qv E c E f E v E c E f E v qv W bi dep q q x n Bn Bn s C W dep ( E A c kt ln E E f N N d d c ) s( Vbi V qn max R ) end x Question: How should we plot the CV data to extract bi? s n Fig. 9.4: Using C-V Data to Determine B Tennessee Technological University Wednesday, October 30,

16 Exercise 1. Consider a contact between Tungsten and an n-type Silicon doped to N d = cm -3 at T = 300K. Calculate the theoretical barrier height, built-in potential barrier and maximum electric field in the metal-semiconductor diode for a zero applied bias. Use the metal work function for Tungsten as M = 4.55V and electron affinity for Silicon = 4.01V. 0 ( B M ) Vbi ( 0 n) B W dep x n s( Vbi V qn d R ) Emax en x d n s Tennessee Technological University Wednesday, October 30,

17 Solution B0 is the ideal Schottky barrier height. B0 ( M ) V The space charge width at a zero bias is: 19 kt N c.8x10 n ln 0.059ln 0. 06V 16 e N d 10 V bi ( B0 n) V W dep x n 14 s ( V bi V R ) (11.7 )( 8.85 * 10 )( 0.33 ) * 10 cm qn (1.6 * 10 )(10 ) d E max end x s n (1.6*10 )(10 )(0.07*10 14 (11.7)(8.85*10 ) 4 ) 3.*10 4 V / cm Tennessee Technological University Wednesday, October 30,

18 The Schottky Barrier Diode Using CV Data to Determine B 1/C 1 C ( bi V ) qn A d s q Bn q bi E c E f V E bi v Fig. 9.5: Using C-V Data to Determine C Tennessee Technological University Wednesday, October 30,

19 The Schottky Barrier Diode v thx - q( B V) E c V Metal N-type Silicon E fm q B qv E fn E v n v J th N SM c e q( V )/ kt 3kT J 1 st B / m e n qnv thx qv / kt mn kt h v thx 4qmnk 3 h, where J st 3/ kt T e e 100e q( V )/ kt / m n q / kt B B q / kt B e qv / kt A/cm Tennessee Technological University Wednesday, October 30, x Richardson's Constant A * 4qmnk 3 h

20 The Schottky Barrier Diode Schottky Diodes V = 0 Forward biased I Reverse biased Reverse bias V Forward bias Tennessee Technological University Wednesday, October 30, 013 0

21 The Schottky Barrier Diode Schottky Diodes I 0 A I * I * A KT 4qmnk 3 h I SM e q / kt B M S 100 A/(cm I st e qv / kt K I st ) I st 1) Tennessee Technological University Wednesday, October 30, ( e qv / kt Richardson's Constant A * 4qmn k 3 h

22 The Schottky Barrier Diode Applications of Schottky Diodes I I Schottky diode I I st ( e qv / kt 1) I st AKT e q / kt B B PN junction diode I st of a Schottky diode is 10 3 to 10 8 times larger than a PN junction diode, depending on B. Alarger I 0 means a smaller forward drop V. A Schottky diode is the preferred rectifier in low voltage, high current applications. V Tennessee Technological University Wednesday, October 30, 013

23 Exercise. Consider a Tungsten-Silicon diode with a barrier height of BN = 0.67V and J st =6*10-5 A/cm. Calculate the effective Richardson constant. J st * A T e q Bn / kt Richardson's Constant A * 4qmnk 3 h Tennessee Technological University Wednesday, October 30, 013 3

24 Solution 1. Using the relation for the reverse saturation current density: J st * A T e q Bn / kt A * J T st qbn / kt e 114 K A cm Tennessee Technological University Wednesday, October 30, 013 4

25 The Schottky Barrier Diode 110V/0V AC utility power PN Junction rectifier Hi-voltage 100kHz Hi-voltage Transformer Lo-voltage Schottky rectifier 50A DC AC AC 1V MOSFET DC inverter feedback to modulate the pulse width to keep V out = 1V Fig. 9.6: Switching Power Supply Tennessee Technological University Wednesday, October 30, 013 5

26 Applications of Schottky Barrier Diode Synchronous Rectifier: For an even lower forward drop, replace the diode with a wide-w MOSFET which is not bound by the tradeoff between diode V and leakage current. There is no minority carrier injection at the Schottky junction. Therefore, Schottky diodes can operate at higher frequencies than PN junction diodes. Tennessee Technological University Wednesday, October 30, 013 6

27 Comparison of Schottky Barrier Diode and the PN Junction Diode The ideal current-voltage relationship of the Schottky barrier diode are of the same form as the PN Junction Diode, there is only a magnitude difference in the reverse-saturation current densities and the switching characteristics. The current in a PN Junction is determined by the diffusion of minority carriers while the current in a Schottky barrier diode is determined by thermionic emission of majority carriers over a potential barrier. The effective turn-on voltage of the Schottky diode is less than the PN Junction diode. The Schottky diode is a high-frequency device than the PN Junction diode, therefore can be used in fast-switching application in pico-second time. Tennessee Technological University Wednesday, October 30, 013 7

28 Picture Credits Semiconductor Physics and Devices, Donald Neaman, 4th Edition, McGraw Hill Publications. Modern Semiconductor Devices for Integrated Circuits, Prof. Chenming Calvin Hu, UC Berkeley (Free e-book Download) Tennessee Technological University Wednesday, October 30, 013 8

PHYSICAL ELECTRONICS(ECE3540) CHAPTER 9 METAL SEMICONDUCTOR AND SEMICONDUCTOR HETERO-JUNCTIONS

PHYSICAL ELECTRONICS(ECE3540) CHAPTER 9 METAL SEMICONDUCTOR AND SEMICONDUCTOR HETERO-JUNCTIONS PHYSICAL ELECTRONICS(ECE3540) CHAPTER 9 METAL SEMICONDUCTOR AND SEMICONDUCTOR HETERO-JUNCTIONS Tennessee Technological University Monday, November 11, 013 1 Introduction Chapter 4: we considered the semiconductor

More information

Schottky Rectifiers Zheng Yang (ERF 3017,

Schottky Rectifiers Zheng Yang (ERF 3017, ECE442 Power Semiconductor Devices and Integrated Circuits Schottky Rectifiers Zheng Yang (ERF 3017, email: yangzhen@uic.edu) Power Schottky Rectifier Structure 2 Metal-Semiconductor Contact The work function

More information

Chapter 7. The pn Junction

Chapter 7. The pn Junction Chapter 7 The pn Junction Chapter 7 PN Junction PN junction can be fabricated by implanting or diffusing donors into a P-type substrate such that a layer of semiconductor is converted into N type. Converting

More information

Current mechanisms Exam January 27, 2012

Current mechanisms Exam January 27, 2012 Current mechanisms Exam January 27, 2012 There are four mechanisms that typically cause currents to flow: thermionic emission, diffusion, drift, and tunneling. Explain briefly which kind of current mechanisms

More information

Schottky diodes. JFETs - MESFETs - MODFETs

Schottky diodes. JFETs - MESFETs - MODFETs Technische Universität Graz Institute of Solid State Physics Schottky diodes JFETs - MESFETs - MODFETs Quasi Fermi level When the charge carriers are not in equilibrium the Fermi energy can be different

More information

Avalanche breakdown. Impact ionization causes an avalanche of current. Occurs at low doping

Avalanche breakdown. Impact ionization causes an avalanche of current. Occurs at low doping Avalanche breakdown Impact ionization causes an avalanche of current Occurs at low doping Zener tunneling Electrons tunnel from valence band to conduction band Occurs at high doping Tunneling wave decays

More information

8. Schottky contacts / JFETs

8. Schottky contacts / JFETs Technische Universität Graz Institute of Solid State Physics 8. Schottky contacts / JFETs Nov. 21, 2018 Technische Universität Graz Institute of Solid State Physics metal - semiconductor contacts Photoelectric

More information

Schottky Diodes (M-S Contacts)

Schottky Diodes (M-S Contacts) Schottky Diodes (M-S Contacts) Three MITs of the Day Band diagrams for ohmic and rectifying Schottky contacts Similarity to and difference from bipolar junctions on electrostatic and IV characteristics.

More information

Lecture 9: Metal-semiconductor junctions

Lecture 9: Metal-semiconductor junctions Lecture 9: Metal-semiconductor junctions Contents 1 Introduction 1 2 Metal-metal junction 1 2.1 Thermocouples.......................... 2 3 Schottky junctions 4 3.1 Forward bias............................

More information

Semiconductor Device Physics

Semiconductor Device Physics 1 emiconductor Device Physics Lecture 8 http://zitompul.wordpress.com 2 0 1 3 emiconductor Device Physics 2 M Contacts and chottky Diodes 3 M Contact The metal-semiconductor (M) contact plays a very important

More information

Semiconductor Physics and Devices

Semiconductor Physics and Devices The pn Junction 1) Charge carriers crossing the junction. 3) Barrier potential Semiconductor Physics and Devices Chapter 8. The pn Junction Diode 2) Formation of positive and negative ions. 4) Formation

More information

Metal Semiconductor Contacts

Metal Semiconductor Contacts Metal Semiconductor Contacts The investigation of rectification in metal-semiconductor contacts was first described by Braun [33-35], who discovered in 1874 the asymmetric nature of electrical conduction

More information

Semiconductor Physics Problems 2015

Semiconductor Physics Problems 2015 Semiconductor Physics Problems 2015 Page and figure numbers refer to Semiconductor Devices Physics and Technology, 3rd edition, by SM Sze and M-K Lee 1. The purest semiconductor crystals it is possible

More information

Thermionic Emission Theory

Thermionic Emission Theory hapter 4. PN and Metal-Semiconductor Junction Thermionic Emiion Theory Energy band diagram of a Schottky contact with a forward bia V applied between the metal and the emiconductor. Electron concentration

More information

EECS130 Integrated Circuit Devices

EECS130 Integrated Circuit Devices EECS130 Integrated Circuit Devices Professor Ali Javey 9/18/2007 P Junctions Lecture 1 Reading: Chapter 5 Announcements For THIS WEEK OLY, Prof. Javey's office hours will be held on Tuesday, Sept 18 3:30-4:30

More information

ECE 340 Lecture 35 : Metal- Semiconductor Junctions Class Outline:

ECE 340 Lecture 35 : Metal- Semiconductor Junctions Class Outline: ECE 340 Lecture 35 : - Junctions Class Outline: Ideal - Contacts Rectifying Contacts Ohmic Contacts Things you should know when you leave Key Questions What happens to the bands when we make contact between

More information

Session 6: Solid State Physics. Diode

Session 6: Solid State Physics. Diode Session 6: Solid State Physics Diode 1 Outline A B C D E F G H I J 2 Definitions / Assumptions Homojunction: the junction is between two regions of the same material Heterojunction: the junction is between

More information

Semiconductor Physics fall 2012 problems

Semiconductor Physics fall 2012 problems Semiconductor Physics fall 2012 problems 1. An n-type sample of silicon has a uniform density N D = 10 16 atoms cm -3 of arsenic, and a p-type silicon sample has N A = 10 15 atoms cm -3 of boron. For each

More information

EECS130 Integrated Circuit Devices

EECS130 Integrated Circuit Devices EECS130 Integrated Circuit Devices Professor Ali Javey 10/02/2007 MS Junctions, Lecture 2 MOS Cap, Lecture 1 Reading: finish chapter14, start chapter16 Announcements Professor Javey will hold his OH at

More information

Introduction to Power Semiconductor Devices

Introduction to Power Semiconductor Devices ECE442 Power Semiconductor Devices and Integrated Circuits Introduction to Power Semiconductor Devices Zheng Yang (ERF 3017, email: yangzhen@uic.edu) Power Semiconductor Devices Applications System Ratings

More information

PN Junction

PN Junction P Junction 2017-05-04 Definition Power Electronics = semiconductor switches are used Analogue amplifier = high power loss 250 200 u x 150 100 u Udc i 50 0 0 50 100 150 200 250 300 350 400 i,u dc i,u u

More information

Semiconductor Physics fall 2012 problems

Semiconductor Physics fall 2012 problems Semiconductor Physics fall 2012 problems 1. An n-type sample of silicon has a uniform density N D = 10 16 atoms cm -3 of arsenic, and a p-type silicon sample has N A = 10 15 atoms cm -3 of boron. For each

More information

UNIVERSITY OF CALIFORNIA College of Engineering Department of Electrical Engineering and Computer Sciences. Professor Chenming Hu.

UNIVERSITY OF CALIFORNIA College of Engineering Department of Electrical Engineering and Computer Sciences. Professor Chenming Hu. UNIVERSITY OF CALIFORNIA College of Engineering Department of Electrical Engineering and Computer Sciences EECS 130 Spring 2009 Professor Chenming Hu Midterm I Name: Closed book. One sheet of notes is

More information

Figure 3.1 (p. 141) Figure 3.2 (p. 142)

Figure 3.1 (p. 141) Figure 3.2 (p. 142) Figure 3.1 (p. 141) Allowed electronic-energy-state systems for two isolated materials. States marked with an X are filled; those unmarked are empty. System 1 is a qualitative representation of a metal;

More information

Fundamentals of Semiconductor Physics

Fundamentals of Semiconductor Physics Fall 2007 Fundamentals of Semiconductor Physics 万 歆 Zhejiang Institute of Modern Physics xinwan@zimp.zju.edu.cn http://zimp.zju.edu.cn/~xinwan/ Transistor technology evokes new physics The objective of

More information

Peak Electric Field. Junction breakdown occurs when the peak electric field in the PN junction reaches a critical value. For the N + P junction,

Peak Electric Field. Junction breakdown occurs when the peak electric field in the PN junction reaches a critical value. For the N + P junction, Peak Electric Field Junction breakdown occurs when the peak electric field in the P junction reaches a critical value. For the + P junction, qa E ( x) ( xp x), s W dep 2 s ( bi Vr ) 2 s potential barrier

More information

Review Energy Bands Carrier Density & Mobility Carrier Transport Generation and Recombination

Review Energy Bands Carrier Density & Mobility Carrier Transport Generation and Recombination Review Energy Bands Carrier Density & Mobility Carrier Transport Generation and Recombination The Metal-Semiconductor Junction: Review Energy band diagram of the metal and the semiconductor before (a)

More information

For the following statements, mark ( ) for true statement and (X) for wrong statement and correct it.

For the following statements, mark ( ) for true statement and (X) for wrong statement and correct it. Benha University Faculty of Engineering Shoubra Electrical Engineering Department First Year communications. Answer all the following questions Illustrate your answers with sketches when necessary. The

More information

Consider a uniformly doped PN junction, in which one region of the semiconductor is uniformly doped with acceptor atoms and the adjacent region is

Consider a uniformly doped PN junction, in which one region of the semiconductor is uniformly doped with acceptor atoms and the adjacent region is CHAPTER 7 The PN Junction Consider a uniformly doped PN junction, in which one region of the semiconductor is uniformly doped with acceptor atoms and the adjacent region is uniformly doped with donor atoms.

More information

Final Examination EE 130 December 16, 1997 Time allotted: 180 minutes

Final Examination EE 130 December 16, 1997 Time allotted: 180 minutes Final Examination EE 130 December 16, 1997 Time allotted: 180 minutes Problem 1: Semiconductor Fundamentals [30 points] A uniformly doped silicon sample of length 100µm and cross-sectional area 100µm 2

More information

n N D n p = n i p N A

n N D n p = n i p N A Summary of electron and hole concentration in semiconductors Intrinsic semiconductor: E G n kt i = pi = N e 2 0 Donor-doped semiconductor: n N D where N D is the concentration of donor impurity Acceptor-doped

More information

1 Name: Student number: DEPARTMENT OF PHYSICS AND PHYSICAL OCEANOGRAPHY MEMORIAL UNIVERSITY OF NEWFOUNDLAND. Fall :00-11:00

1 Name: Student number: DEPARTMENT OF PHYSICS AND PHYSICAL OCEANOGRAPHY MEMORIAL UNIVERSITY OF NEWFOUNDLAND. Fall :00-11:00 1 Name: DEPARTMENT OF PHYSICS AND PHYSICAL OCEANOGRAPHY MEMORIAL UNIVERSITY OF NEWFOUNDLAND Final Exam Physics 3000 December 11, 2012 Fall 2012 9:00-11:00 INSTRUCTIONS: 1. Answer all seven (7) questions.

More information

Module-6: Schottky barrier capacitance-impurity concentration

Module-6: Schottky barrier capacitance-impurity concentration 6.1 Introduction: Module-6: Schottky barrier capacitance-impurity concentration The electric current flowing across a metal semiconductor interface is generally non-linear with respect to the applied bias

More information

Lecture 2. Introduction to semiconductors Structures and characteristics in semiconductors

Lecture 2. Introduction to semiconductors Structures and characteristics in semiconductors Lecture 2 Introduction to semiconductors Structures and characteristics in semiconductors Semiconductor p-n junction Metal Oxide Silicon structure Semiconductor contact Literature Glen F. Knoll, Radiation

More information

Lecture 15 - The pn Junction Diode (I) I-V Characteristics. November 1, 2005

Lecture 15 - The pn Junction Diode (I) I-V Characteristics. November 1, 2005 6.012 - Microelectronic Devices and Circuits - Fall 2005 Lecture 15-1 Lecture 15 - The pn Junction Diode (I) I-V Characteristics November 1, 2005 Contents: 1. pn junction under bias 2. I-V characteristics

More information

UNIVERSITY OF CALIFORNIA College of Engineering Department of Electrical Engineering and Computer Sciences. EECS 130 Professor Ali Javey Fall 2006

UNIVERSITY OF CALIFORNIA College of Engineering Department of Electrical Engineering and Computer Sciences. EECS 130 Professor Ali Javey Fall 2006 UNIVERSITY OF CALIFORNIA College of Engineering Department of Electrical Engineering and Computer Sciences EECS 130 Professor Ali Javey Fall 2006 Midterm 2 Name: SID: Closed book. Two sheets of notes are

More information

Semiconductor Physics. Lecture 6

Semiconductor Physics. Lecture 6 Semiconductor Physics Lecture 6 Recap pn junction and the depletion region Driven by the need to have no gradient in the fermi level free carriers migrate across the pn junction leaving a region with few

More information

Lecture 2. Introduction to semiconductors Structures and characteristics in semiconductors. Fabrication of semiconductor sensor

Lecture 2. Introduction to semiconductors Structures and characteristics in semiconductors. Fabrication of semiconductor sensor Lecture 2 Introduction to semiconductors Structures and characteristics in semiconductors Semiconductor p-n junction Metal Oxide Silicon structure Semiconductor contact Fabrication of semiconductor sensor

More information

Effective masses in semiconductors

Effective masses in semiconductors Effective masses in semiconductors The effective mass is defined as: In a solid, the electron (hole) effective mass represents how electrons move in an applied field. The effective mass reflects the inverse

More information

Diodes. EE223 Digital & Analogue Electronics Derek Molloy 2012/2013.

Diodes. EE223 Digital & Analogue Electronics Derek Molloy 2012/2013. Diodes EE223 Digital & Analogue Electronics Derek Molloy 2012/2013 Derek.Molloy@dcu.ie Diodes: A Semiconductor? Conductors Such as copper, aluminium have a cloud of free electrons weak bound valence electrons

More information

6.012 Electronic Devices and Circuits

6.012 Electronic Devices and Circuits Page 1 of 1 YOUR NAME Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology 6.12 Electronic Devices and Circuits Exam No. 1 Wednesday, October 7, 29 7:3 to 9:3

More information

Lecture 2. Introduction to semiconductors Structures and characteristics in semiconductors

Lecture 2. Introduction to semiconductors Structures and characteristics in semiconductors Lecture 2 Introduction to semiconductors Structures and characteristics in semiconductors Semiconductor p-n junction Metal Oxide Silicon structure Semiconductor contact Literature Glen F. Knoll, Radiation

More information

EE 130 Intro to MS Junctions Week 6 Notes. What is the work function? Energy to excite electron from Fermi level to the vacuum level

EE 130 Intro to MS Junctions Week 6 Notes. What is the work function? Energy to excite electron from Fermi level to the vacuum level EE 13 Intro to S Junctions eek 6 Notes Problem 1 hat is the work function? Energy to ecite electron from Fermi level to the vacuum level Electron affinity of 4.5eV Electron affinity of Ge 4.eV orkfunction

More information

Midterm I - Solutions

Midterm I - Solutions UNIVERSITY OF CALIFORNIA College of Engineering Department of Electrical Engineering and Computer Sciences EECS 130 Spring 2008 Professor Chenming Hu Midterm I - Solutions Name: SID: Grad/Undergrad: Closed

More information

Semiconductor Junctions

Semiconductor Junctions 8 Semiconductor Junctions Almost all solar cells contain junctions between different materials of different doping. Since these junctions are crucial to the operation of the solar cell, we will discuss

More information

Thermionic emission vs. drift-diffusion vs. p-n junction

Thermionic emission vs. drift-diffusion vs. p-n junction 6.772/SMA5111 - Compound Semiconductors Lecture 4 - Carrier flow in heterojunctions - Outline A look at current models for m-s junctions (old business) Thermionic emission vs. drift-diffusion vs. p-n junction

More information

Section 12: Intro to Devices

Section 12: Intro to Devices Section 12: Intro to Devices Extensive reading materials on reserve, including Robert F. Pierret, Semiconductor Device Fundamentals Bond Model of Electrons and Holes Si Si Si Si Si Si Si Si Si Silicon

More information

3. Two-dimensional systems

3. Two-dimensional systems 3. Two-dimensional systems Image from IBM-Almaden 1 Introduction Type I: natural layered structures, e.g., graphite (with C nanostructures) Type II: artificial structures, heterojunctions Great technological

More information

PN Junctions. Lecture 7

PN Junctions. Lecture 7 Lecture 7 PN Junctions Kathy Aidala Applied Physics, G2 Harvard University 10 October, 2002 Wei 1 Active Circuit Elements Why are they desirable? Much greater flexibility in circuit applications. What

More information

Lecture 04 Review of MOSFET

Lecture 04 Review of MOSFET ECE 541/ME 541 Microelectronic Fabrication Techniques Lecture 04 Review of MOSFET Zheng Yang (ERF 3017, email: yangzhen@uic.edu) What is a Transistor? A Switch! An MOS Transistor V GS V T V GS S Ron D

More information

Junction Diodes. Tim Sumner, Imperial College, Rm: 1009, x /18/2006

Junction Diodes. Tim Sumner, Imperial College, Rm: 1009, x /18/2006 Junction Diodes Most elementary solid state junction electronic devices. They conduct in one direction (almost correct). Useful when one converts from AC to DC (rectifier). But today diodes have a wide

More information

Semiconductor Devices

Semiconductor Devices Semiconductor Devices - 2014 Lecture Course Part of SS Module PY4P03 Dr. P. Stamenov School of Physics and CRANN, Trinity College, Dublin 2, Ireland Hilary Term, TCD 17 th of Jan 14 Metal-Semiconductor

More information

junctions produce nonlinear current voltage characteristics which can be exploited

junctions produce nonlinear current voltage characteristics which can be exploited Chapter 6 P-N DODES Junctions between n-and p-type semiconductors are extremely important foravariety of devices. Diodes based on p-n junctions produce nonlinear current voltage characteristics which can

More information

ECE 340 Lecture 27 : Junction Capacitance Class Outline:

ECE 340 Lecture 27 : Junction Capacitance Class Outline: ECE 340 Lecture 27 : Junction Capacitance Class Outline: Breakdown Review Junction Capacitance Things you should know when you leave M.J. Gilbert ECE 340 Lecture 27 10/24/11 Key Questions What types of

More information

ECE321 Electronics I

ECE321 Electronics I ECE321 Electronics I Lecture 4: Physics of Semiconductor iodes Payman Zarkesh-Ha Office: ECE Bldg. 230B Office hours: Tuesday 2:00-3:00PM or by appointment E-mail: pzarkesh.unm.edu Slide: 1 Review of Last

More information

Introductory Nanotechnology ~ Basic Condensed Matter Physics ~

Introductory Nanotechnology ~ Basic Condensed Matter Physics ~ Introductory Nanotechnology ~ Basic Condensed Matter Physics ~ Atsufumi Hirohata Department of Electronics Quick Review over the Last Lecture Classic model : Dulong-Petit empirical law c V, mol 3R 0 E

More information

Electronic PRINCIPLES

Electronic PRINCIPLES MALVINO & BATES Electronic PRINCIPLES SEVENTH EDITION Chapter 2 Semiconductors Topics Covered in Chapter 2 Conductors Semiconductors Silicon crystals Intrinsic semiconductors Two types of flow Doping a

More information

Metal Semiconductor Contacts

Metal Semiconductor Contacts 10 Metal Semiconductor Contacts 10.1. Introduction In this chapter, the basic device physics, the electrical and transport properties, the formation and characterization of various metal semiconductor

More information

Electronic Circuits for Mechatronics ELCT 609 Lecture 2: PN Junctions (1)

Electronic Circuits for Mechatronics ELCT 609 Lecture 2: PN Junctions (1) Electronic Circuits for Mechatronics ELCT 609 Lecture 2: PN Junctions (1) Assistant Professor Office: C3.315 E-mail: eman.azab@guc.edu.eg 1 Electronic (Semiconductor) Devices P-N Junctions (Diodes): Physical

More information

SRI VIDYA COLLEGE OF ENGINEERING AND TECHNOLOGY VIRUDHUNAGAR Department of Electronics and Communication Engineering

SRI VIDYA COLLEGE OF ENGINEERING AND TECHNOLOGY VIRUDHUNAGAR Department of Electronics and Communication Engineering SRI VIDYA COLLEGE OF ENGINEERING AND TECHNOLOGY VIRUDHUNAGAR Department of Electronics and Communication Engineering Class/Sem:I ECE/II Question Bank for EC6201-ELECTRONIC DEVICES 1.What do u meant by

More information

Sample Exam # 2 ECEN 3320 Fall 2013 Semiconductor Devices October 28, 2013 Due November 4, 2013

Sample Exam # 2 ECEN 3320 Fall 2013 Semiconductor Devices October 28, 2013 Due November 4, 2013 Sample Exam # 2 ECEN 3320 Fall 203 Semiconductor Devices October 28, 203 Due November 4, 203. Below is the capacitance-voltage curve measured from a Schottky contact made on GaAs at T 300 K. Figure : Capacitance

More information

Lecture 17 - p-n Junction. October 11, Ideal p-n junction in equilibrium 2. Ideal p-n junction out of equilibrium

Lecture 17 - p-n Junction. October 11, Ideal p-n junction in equilibrium 2. Ideal p-n junction out of equilibrium 6.72J/3.43J - Integrated Microelectronic Devices - Fall 22 Lecture 17-1 Lecture 17 - p-n Junction October 11, 22 Contents: 1. Ideal p-n junction in equilibrium 2. Ideal p-n junction out of equilibrium

More information

Semiconductor Detectors

Semiconductor Detectors Semiconductor Detectors Summary of Last Lecture Band structure in Solids: Conduction band Conduction band thermal conductivity: E g > 5 ev Valence band Insulator Charge carrier in conductor: e - Charge

More information

Electronics The basics of semiconductor physics

Electronics The basics of semiconductor physics Electronics The basics of semiconductor physics Prof. Márta Rencz, Gergely Nagy BME DED September 16, 2013 The basic properties of semiconductors Semiconductors conductance is between that of conductors

More information

MOS CAPACITOR AND MOSFET

MOS CAPACITOR AND MOSFET EE336 Semiconductor Devices 1 MOS CAPACITOR AND MOSFET Dr. Mohammed M. Farag Ideal MOS Capacitor Semiconductor Devices Physics and Technology Chapter 5 EE336 Semiconductor Devices 2 MOS Capacitor Structure

More information

Electrical Characteristics of MOS Devices

Electrical Characteristics of MOS Devices Electrical Characteristics of MOS Devices The MOS Capacitor Voltage components Accumulation, Depletion, Inversion Modes Effect of channel bias and substrate bias Effect of gate oide charges Threshold-voltage

More information

CHAPTER 4: P-N P N JUNCTION Part 2. M.N.A. Halif & S.N. Sabki

CHAPTER 4: P-N P N JUNCTION Part 2. M.N.A. Halif & S.N. Sabki CHAPTER 4: P-N P N JUNCTION Part 2 Part 2 Charge Storage & Transient Behavior Junction Breakdown Heterojunction CHARGE STORAGE & TRANSIENT BEHAVIOR Once injected across the junction, the minority carriers

More information

ECE 305 Exam 2: Spring 2017 March 10, 2017 Muhammad Alam Purdue University

ECE 305 Exam 2: Spring 2017 March 10, 2017 Muhammad Alam Purdue University NAME: PUID: : ECE 305 Exam 2: Spring 2017 March 10, 2017 Muhammad Alam Purdue University This is a closed book exam You may use a calculator and the formula sheet Following the ECE policy, the calculator

More information

Solid State Electronics. Final Examination

Solid State Electronics. Final Examination The University of Toledo EECS:4400/5400/7400 Solid State Electronic Section elssf08fs.fm - 1 Solid State Electronics Final Examination Problems Points 1. 1. 14 3. 14 Total 40 Was the exam fair? yes no

More information

PHYS208 P-N Junction. Olav Torheim. May 30, 2007

PHYS208 P-N Junction. Olav Torheim. May 30, 2007 1 PHYS208 P-N Junction Olav Torheim May 30, 2007 1 Intrinsic semiconductors The lower end of the conduction band is a parabola, just like in the quadratic free electron case (E = h2 k 2 2m ). The density

More information

The Law of the Junction Revisited. Mark Lundstrom Network for Computational Nanotechnology and Purdue University ( ). (1)

The Law of the Junction Revisited. Mark Lundstrom Network for Computational Nanotechnology and Purdue University ( ). (1) The Law of the Junction Revisited Mark Lundstrom Network for Computational Nanotechnology and Purdue University Consider a one-sided, short base diode like that shown in Fig.. We usually analyze the I-V

More information

Hussein Ayedh. PhD Studet Department of Physics

Hussein Ayedh. PhD Studet Department of Physics Hussein Ayedh PhD Studet Department of Physics OUTLINE Introduction Semiconductors Basics DLTS Theory DLTS Requirements Example Summary Introduction Energetically "deep trapping levels in semiconductor

More information

OPTI510R: Photonics. Khanh Kieu College of Optical Sciences, University of Arizona Meinel building R.626

OPTI510R: Photonics. Khanh Kieu College of Optical Sciences, University of Arizona Meinel building R.626 OPTI510R: Photonics Khanh Kieu College of Optical Sciences, University of Arizona kkieu@optics.arizona.edu Meinel building R.626 Announcements Homework #6 is assigned, due May 1 st Final exam May 8, 10:30-12:30pm

More information

Determination of properties in semiconductor materials by applying Matlab

Determination of properties in semiconductor materials by applying Matlab Determination of properties in semiconductor materials by applying Matlab Carlos Figueroa. 1, Raúl Riera A. 2 1 Departamento de Ingeniería Industrial. Universidad de Sonora A.P. 5-088, Hermosillo, Sonora.

More information

Spring Semester 2012 Final Exam

Spring Semester 2012 Final Exam Spring Semester 2012 Final Exam Note: Show your work, underline results, and always show units. Official exam time: 2.0 hours; an extension of at least 1.0 hour will be granted to anyone. Materials parameters

More information

Lecture (02) PN Junctions and Diodes

Lecture (02) PN Junctions and Diodes Lecture (02) PN Junctions and Diodes By: Dr. Ahmed ElShafee ١ I Agenda N type, P type semiconductors N Type Semiconductor P Type Semiconductor PN junction Energy Diagrams of the PN Junction and Depletion

More information

MTLE-6120: Advanced Electronic Properties of Materials. Semiconductor p-n junction diodes. Reading: Kasap ,

MTLE-6120: Advanced Electronic Properties of Materials. Semiconductor p-n junction diodes. Reading: Kasap , MTLE-6120: Advanced Electronic Properties of Materials 1 Semiconductor p-n junction diodes Reading: Kasap 6.1-6.5, 6.9-6.12 Metal-semiconductor contact potential 2 p-type n-type p-type n-type Same semiconductor

More information

PN Junction and MOS structure

PN Junction and MOS structure PN Junction and MOS structure Basic electrostatic equations We will use simple one-dimensional electrostatic equations to develop insight and basic understanding of how semiconductor devices operate Gauss's

More information

The pn junction. [Fonstad, Ghione]

The pn junction. [Fonstad, Ghione] The pn junction [Fonstad, Ghione] Band diagram On the vertical axis: potential energy of the electrons On the horizontal axis: now there is nothing: later we ll put the position qf s : work function (F

More information

V BI. H. Föll: kiel.de/matwis/amat/semi_en/kap_2/backbone/r2_2_4.html. different electrochemical potentials (i.e.

V BI. H. Föll:  kiel.de/matwis/amat/semi_en/kap_2/backbone/r2_2_4.html. different electrochemical potentials (i.e. Consider the the band diagram for a homojunction, formed when two bits of the same type of semicondutor (e.g. Si) are doped p and ntype and then brought into contact. Electrons in the two bits have different

More information

UNIVERSITY OF CALIFORNIA College of Engineering Department of Electrical Engineering and Computer Sciences. EECS 130 Professor Ali Javey Fall 2006

UNIVERSITY OF CALIFORNIA College of Engineering Department of Electrical Engineering and Computer Sciences. EECS 130 Professor Ali Javey Fall 2006 UNIVERSITY OF CALIFORNIA College of Engineering Department of Electrical Engineering and Computer Sciences EECS 130 Professor Ali Javey Fall 2006 Midterm I Name: Closed book. One sheet of notes is allowed.

More information

Lecture 15 The pn Junction Diode (II)

Lecture 15 The pn Junction Diode (II) Lecture 15 The pn Junction Diode (II I-V characteristics Forward Bias Reverse Bias Outline Reading Assignment: Howe and Sodini; Chapter 6, Sections 6.4-6.5 6.012 Spring 2007 Lecture 15 1 1. I-V Characteristics

More information

R. Ludwig and G. Bogdanov RF Circuit Design: Theory and Applications 2 nd edition. Figures for Chapter 6

R. Ludwig and G. Bogdanov RF Circuit Design: Theory and Applications 2 nd edition. Figures for Chapter 6 R. Ludwig and G. Bogdanov RF Circuit Design: Theory and Applications 2 nd edition Figures for Chapter 6 Free electron Conduction band Hole W g W C Forbidden Band or Bandgap W V Electron energy Hole Valence

More information

Surfaces, Interfaces, and Layered Devices

Surfaces, Interfaces, and Layered Devices Surfaces, Interfaces, and Layered Devices Building blocks for nanodevices! W. Pauli: God made solids, but surfaces were the work of Devil. Surfaces and Interfaces 1 Interface between a crystal and vacuum

More information

Lecture-4 Junction Diode Characteristics

Lecture-4 Junction Diode Characteristics 1 Lecture-4 Junction Diode Characteristics Part-II Q: Aluminum is alloyed into n-type Si sample (N D = 10 16 cm 3 ) forming an abrupt junction of circular cross-section, with an diameter of 0.02 in. Assume

More information

- A free electron in CB "meets" a hole in VB: the excess energy -> a photon energy.

- A free electron in CB meets a hole in VB: the excess energy -> a photon energy. 5.4. Recombination and Minority Carrier Injection 5.4.1 Direct and Indirect Recombination A free electron in CB "meets" a hole in VB: the excess energy > a photon energy. Energy CB ψ cb (k cb ) ψ vb (k

More information

L03: pn Junctions, Diodes

L03: pn Junctions, Diodes 8/30/2012 Page 1 of 5 Reference:C:\Users\Bernhard Boser\Documents\Files\Lib\MathCAD\Default\defaults.mcd L03: pn Junctions, Diodes Intrinsic Si Q: What are n, p? Q: Is the Si charged? Q: How could we make

More information

ISSUES TO ADDRESS...

ISSUES TO ADDRESS... Chapter 12: Electrical Properties School of Mechanical Engineering Choi, Hae-Jin Materials Science - Prof. Choi, Hae-Jin Chapter 12-1 ISSUES TO ADDRESS... How are electrical conductance and resistance

More information

This is the 15th lecture of this course in which we begin a new topic, Excess Carriers. This topic will be covered in two lectures.

This is the 15th lecture of this course in which we begin a new topic, Excess Carriers. This topic will be covered in two lectures. Solid State Devices Dr. S. Karmalkar Department of Electronics and Communication Engineering Indian Institute of Technology, Madras Lecture - 15 Excess Carriers This is the 15th lecture of this course

More information

Section 12: Intro to Devices

Section 12: Intro to Devices Section 12: Intro to Devices Extensive reading materials on reserve, including Robert F. Pierret, Semiconductor Device Fundamentals EE143 Ali Javey Bond Model of Electrons and Holes Si Si Si Si Si Si Si

More information

Lecture 12: MOS Capacitors, transistors. Context

Lecture 12: MOS Capacitors, transistors. Context Lecture 12: MOS Capacitors, transistors Context In the last lecture, we discussed PN diodes, and the depletion layer into semiconductor surfaces. Small signal models In this lecture, we will apply those

More information

Concept of Core IENGINEERS- CONSULTANTS LECTURE NOTES SERIES ELECTRONICS ENGINEERING 1 YEAR UPTU. Page 1

Concept of Core IENGINEERS- CONSULTANTS LECTURE NOTES SERIES ELECTRONICS ENGINEERING 1 YEAR UPTU. Page 1 Concept of Core Conductivity of conductor and semiconductor can also be explained by concept of Core. Core: Core is a part of an atom other than its valence electrons. Core consists of all inner shells

More information

Physics of Semiconductors 8 th

Physics of Semiconductors 8 th Physics of Semiconductors 8 th 2016.6.6 Shingo Katsumoto Department of Physics, Institute for Solid State Physics University of Tokyo Review of pn junction Estimation of builtin potential Depletion layer

More information

Lecture (02) Introduction to Electronics II, PN Junction and Diodes I

Lecture (02) Introduction to Electronics II, PN Junction and Diodes I Lecture (02) Introduction to Electronics II, PN Junction and Diodes I By: Dr. Ahmed ElShafee ١ Agenda Current in semiconductors/conductors N type, P type semiconductors N Type Semiconductor P Type Semiconductor

More information

Lecture 5 Junction characterisation

Lecture 5 Junction characterisation Lecture 5 Junction characterisation Jon Major October 2018 The PV research cycle Make cells Measure cells Despair Repeat 40 1.1% 4.9% Data Current density (ma/cm 2 ) 20 0-20 -1.0-0.5 0.0 0.5 1.0 Voltage

More information

p-n junction biasing, p-n I-V characteristics, p-n currents Norlaili Mohd. Noh EEE /09

p-n junction biasing, p-n I-V characteristics, p-n currents Norlaili Mohd. Noh EEE /09 CLASS 6&7 p-n junction biasing, p-n I-V characteristics, p-n currents 1 p-n junction biasing Unbiased p-n junction: the potential barrier is 0.7 V for Si and 0.3 V for Ge. Nett current across the p-n junction

More information

ECE 305 Fall Final Exam (Exam 5) Wednesday, December 13, 2017

ECE 305 Fall Final Exam (Exam 5) Wednesday, December 13, 2017 NAME: PUID: ECE 305 Fall 017 Final Exam (Exam 5) Wednesday, December 13, 017 This is a closed book exam. You may use a calculator and the formula sheet at the end of this exam. Following the ECE policy,

More information

Diodes. anode. cathode. cut-off. Can be approximated by a piecewise-linear-like characteristic. Lecture 9-1

Diodes. anode. cathode. cut-off. Can be approximated by a piecewise-linear-like characteristic. Lecture 9-1 Diodes mplest nonlinear circuit element Basic operation sets the foundation for Bipolar Junction Transistors (BJTs) Also present in Field Effect Transistors (FETs) Ideal diode characteristic anode cathode

More information

Chap. 11 Semiconductor Diodes

Chap. 11 Semiconductor Diodes Chap. 11 Semiconductor Diodes Semiconductor diodes provide the best resolution for energy measurements, silicon based devices are generally used for charged-particles, germanium for photons. Scintillators

More information

EE 3329 Electronic Devices Syllabus ( Extended Play )

EE 3329 Electronic Devices Syllabus ( Extended Play ) EE 3329 - Electronic Devices Syllabus EE 3329 Electronic Devices Syllabus ( Extended Play ) The University of Texas at El Paso The following concepts can be part of the syllabus for the Electronic Devices

More information