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

Size: px
Start display at page:

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

Transcription

1 6.772/SMA 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 Conduction normal to heterojunctions Current flow: 1. Drift-diffusion 2. Ballistic injection Injection tailoring: decoupling injection from doping (current across HJs) Band-edge spikes: 1. Impact on conduction and evolution with bias: a. Forward flow: i. Barriers to carrier flow; ii. Division of applied bias; iii. Evolution with bias b. Reverse flow: i. impact on collection; ii. evolution with bias 2. Elimination of spikes by composition grading (quasi-fermi level discussion) Conduction parallel to heterojunctions Modulation doped structures: Mobility vs. structure Interface roughness (in-plane action) C. G. Fonstad, 2/03 Lecture 4 - Slide 1

2 Applying bias to a metal-semiconductor junction, review Currents Note: the barrier seen by electrons in the metal does not change with bias, whereas the barrier seen by those in the semiconductor does. Thus the carrier flux (current) we focus on is that of majority carriers from the semiconductor flowing into the metal. Metal-semiconductor junctions are primarily majority carrier devices. qf bm q(f b -V AB ) qf bm qv AB q(f b -v AB ) qv AB Reverse bias Forward bias (Minority carrier injection into the semiconductor can usually be neglected; more about this later) C. G. Fonstad, 2/03 Lecture 4 - Slide 2

3 M-S JUNCTION CURRENT MODELS: General form of net barrier current: comparing models e qv AB / kt i d = A q R N D e -qf b / kt ( -1) Thermionic emission model - ballistic injection over barrier A * T 2 -qf bm / kt (e qv AB / kt i d / A = e -1) * A : Thermionic emission coefficient f : Barrier in metal, = f + (kt /q) ln(n / N ) bm b C D Substituting for f bm and rearranging : A * T 2 -qf b / kt (e qv AB / kt i d / A = q N D e -1) qn C from which we see R TE = A * T 2 /qn C C. G. Fonstad, 2/03 Lecture 4 - Slide 3

4 Drift-diffusion model - drift to and over barrier b e qv AB i / kt d / A = q m e E pk N D e -qf / kt ( -1) where : E : Peak electric field, =E(0) = 2q pk (f b - v AB )N D /e Comparing this to the stan dard form we see : R DD =me E pk, which is the drift velocity at x = 0! Before comparing the thermionic emission and driftdiffusion expressions, we will look at the current through a p-n + junction diode. C. G. Fonstad, 2/03 Lecture 4 - Slide 4

5 P-n + Diode - diffusion away from the barrier i d ª i 2 de D e n = q i (e qv AB / kt -1) A A w p N Ap Ê kt ˆ Ê N Dn N Ap ˆ The barrier at the junction is f b = Á lná 2 Ë q Ë n i from which we find : n i 2 / N Ap and thus : For this diode R + = N D e -qf b / kt i d ª q D e N D e -qf b / kt (e qv AB / kt -1). A w p pn = D e / w p, the diffusion velocity. C. G. Fonstad, 2/03 Lecture 4 - Slide 5

6 Comparing the results - Thermionic emission R TE = A * T 2 /qn C, modeling from metal side Drift-diffusion R DD =m e E pk, the drift velocity at x = 0. p-n + diode R p-n + = D e / w p, the diffusion velocity. C. G. Fonstad, 2/03 Lecture 4 - Slide 6

7 Conduction normal to heterojunctions Emitter efficiency expressions with and without spike, and comparison with homojunction result Grading composition to eliminate spikes: WHITE BOARD Quasi-Fermi levels and built-in effective fields due to band-edge slopes E c / x for electrons, E v / x for holes C. G. Fonstad, 2/03 Lecture 4 - Slide 7

8 Heterojunctions - band picture, depletion approximation Electrically connected: i. Charge shifts between sides ii. Fermi levels shift until equal iii. Vacuum ref. is now -qf(x) where f(x) = (q/e) r(x) dx dx iv. E c (x) is -qf(x) - c(x) and E v (x) = -qf(x) - [c(x) +E g (x)] v. Depletion approximation is a good estimate of r(x) 0 DEc = q(cp - cn) qc p qf sp qc N E cn E fn qf sn Egp E cp E fp E vp EgN E vn DEv = q(cp - cn) + Egp - EgN C. G. Fonstad, 2/03 x Lecture 4 - Slide 8 -x p 0 x n

9 Conduction parallel to heterojunctions Modulation doped structures N-n heterojunctions and accumulated electrons Modulation doped structure with surface pinning and HJ WHITE BOARD Back to foils Carrier scattering and mobilities in accumulated two-dimensional electron gas C. G. Fonstad, 2/03 Lecture 4 - Slide 9

10 Modulation doping - two-dimensional electron gases Components of mobility (Image deleted) GaAs See Fig in: Shur, M.S. Physics of Semiconductor Devices Englewood Cliffs, N.J., Prentice-Hall, Sample doping A: 5 x cm -3 B: cm -3 C: 5 x cm -3 2 C. G. Fonstad, 2/03 Lecture 4 - Slide 10

11 Modulation doping - two-dimensional electron gases Bulk mobilities in GaAs as a function of doping level (at room temperature) (Image deleted) See Ch2 Fig19 in: Sze, S.M. Physics of Semiconductor Device 2nd ed. New York: Wiley, () C. G. Fonstad, 2/03 Lecture 4 - Slide 11

12 Modulation doping - two-dimensional electron gases Improvement of TEG mobility with time (Image deleted) See Fig 60 in: Weisbuch, C. and Vinter, B., Quantum Semiconductor Structures: Fundamentals and Applications Boston: Academic Press, () C. G. Fonstad, 2/03 Lecture 4 - Slide 12

ECE-305: Spring 2018 Exam 2 Review

ECE-305: Spring 2018 Exam 2 Review ECE-305: Spring 018 Exam Review Pierret, Semiconductor Device Fundamentals (SDF) Chapter 3 (pp. 75-138) Chapter 5 (pp. 195-6) Professor Peter Bermel Electrical and Computer Engineering Purdue University,

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

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

ρ ρ LED access resistances d A W d s n s p p p W the output window size p-layer d p series access resistance d n n-layer series access resistance

ρ ρ LED access resistances d A W d s n s p p p W the output window size p-layer d p series access resistance d n n-layer series access resistance LED access resistances W the output window size p-layer series access resistance d p n-layer series access resistance d n The n-layer series access resistance R = ρ s n where the resistivity of the n-layer

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

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 Wednesday, October 30, 013 1 Introduction Chapter 4: we considered the

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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 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

Electronic Devices and Circuits Lecture 5 - p-n Junction Injection and Flow - Outline

Electronic Devices and Circuits Lecture 5 - p-n Junction Injection and Flow - Outline 6.012 - Electronic Devices and Circuits Lecture 5 - p-n Junction Injection and Flow - Outline Review Depletion approimation for an abrupt p-n junction Depletion charge storage and depletion capacitance

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

Recombination: Depletion. Auger, and Tunnelling

Recombination: Depletion. Auger, and Tunnelling Recombination: Depletion Region, Bulk, Radiative, Auger, and Tunnelling Ch 140 Lecture Notes #13 Prepared by David Gleason We assume: Review of Depletion Region Recombination Flat Quantum Fermi Levels

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

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

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

ECE 440 Lecture 20 : PN Junction Electrostatics II Class Outline:

ECE 440 Lecture 20 : PN Junction Electrostatics II Class Outline: ECE 440 Lecture 20 : PN Junction Electrostatics II Class Outline: Depletion Approximation Step Junction Things you should know when you leave Key Questions What is the space charge region? What are the

More information

Bipolar junction transistor operation and modeling

Bipolar junction transistor operation and modeling 6.01 - Electronic Devices and Circuits Lecture 8 - Bipolar Junction Transistor Basics - Outline Announcements Handout - Lecture Outline and Summary; Old eam 1's on Stellar First Hour Eam - Oct. 8, 7:30-9:30

More information

ECE 340 Lecture 21 : P-N Junction II Class Outline:

ECE 340 Lecture 21 : P-N Junction II Class Outline: ECE 340 Lecture 21 : P-N Junction II Class Outline: Contact Potential Equilibrium Fermi Levels Things you should know when you leave Key Questions What is the contact potential? Where does the transition

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

Getting J e (x), J h (x), E(x), and p'(x), knowing n'(x) Solving the diffusion equation for n'(x) (using p-type example)

Getting J e (x), J h (x), E(x), and p'(x), knowing n'(x) Solving the diffusion equation for n'(x) (using p-type example) 6.012 - Electronic Devices and Circuits Lecture 4 - Non-uniform Injection (Flow) Problems - Outline Announcements Handouts - 1. Lecture Outline and Summary; 2. Thermoelectrics Review Thermoelectricity:

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

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

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

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

2.626 Fundamentals of Photovoltaics

2.626 Fundamentals of Photovoltaics MIT OpenCourseWare http://ocw.mit.edu 2.626 Fundamentals of Photovoltaics Fall 2008 For information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms. Charge Separation:

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

Lecture contents. Metal-semiconductor contact

Lecture contents. Metal-semiconductor contact 1 Lecture contents Metal-semiconuctor contact Electrostatics: Full epletion approimation Electrostatics: Eact electrostatic solution Current Methos for barrier measurement Junctions: general approaches,

More information

Electronic Devices and Circuits Lecture 14 - Linear Equivalent Circuits - Outline Announcements

Electronic Devices and Circuits Lecture 14 - Linear Equivalent Circuits - Outline Announcements 6.012 Electronic Devices and Circuits Lecture 14 Linear Equivalent Circuits Outline Announcements Handout Lecture Outline and Summary Review Adding refinements to large signal models Charge stores: depletion

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

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

Band Alignment and Graded Heterostructures. Guofu Niu Auburn University

Band Alignment and Graded Heterostructures. Guofu Niu Auburn University Band Alignment and Graded Heterostructures Guofu Niu Auburn University Outline Concept of electron affinity Types of heterojunction band alignment Band alignment in strained SiGe/Si Cusps and Notches at

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

Quantum and Non-local Transport Models in Crosslight Device Simulators. Copyright 2008 Crosslight Software Inc.

Quantum and Non-local Transport Models in Crosslight Device Simulators. Copyright 2008 Crosslight Software Inc. Quantum and Non-local Transport Models in Crosslight Device Simulators Copyright 2008 Crosslight Software Inc. 1 Introduction Quantization effects Content Self-consistent charge-potential profile. Space

More information

Semiconductor Physics. Lecture 3

Semiconductor Physics. Lecture 3 Semiconductor Physics Lecture 3 Intrinsic carrier density Intrinsic carrier density Law of mass action Valid also if we add an impurity which either donates extra electrons or holes the number of 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

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

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

ECE 440 Lecture 28 : P-N Junction II Class Outline:

ECE 440 Lecture 28 : P-N Junction II Class Outline: ECE 440 Lecture 28 : P-N Junction II Class Outline: Contact Potential Equilibrium Fermi Levels Things you should know when you leave Key Questions What is the contact potential? Where does the transition

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

Classification of Solids

Classification of Solids Classification of Solids Classification by conductivity, which is related to the band structure: (Filled bands are shown dark; D(E) = Density of states) Class Electron Density Density of States D(E) Examples

More information

Long-channel MOSFET IV Corrections

Long-channel MOSFET IV Corrections Long-channel MOSFET IV orrections Three MITs of the Day The body ect and its influence on long-channel V th. Long-channel subthreshold conduction and control (subthreshold slope S) Scattering components

More information

Electronic Devices and Circuits Lecture 15 - Digital Circuits: Inverter Basics - Outline Announcements. = total current; I D

Electronic Devices and Circuits Lecture 15 - Digital Circuits: Inverter Basics - Outline Announcements. = total current; I D 6.012 - Electronic Devices and Circuits Lecture 15 - Digital Circuits: Inverter asics - Outline Announcements Handout - Lecture Outline and Summary The MOSFET alpha factor - use definition in lecture,

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

Semiconductor device structures are traditionally divided into homojunction devices

Semiconductor device structures are traditionally divided into homojunction devices 0. Introduction: Semiconductor device structures are traditionally divided into homojunction devices (devices consisting of only one type of semiconductor material) and heterojunction devices (consisting

More information

Laser Diodes. Revised: 3/14/14 14: , Henry Zmuda Set 6a Laser Diodes 1

Laser Diodes. Revised: 3/14/14 14: , Henry Zmuda Set 6a Laser Diodes 1 Laser Diodes Revised: 3/14/14 14:03 2014, Henry Zmuda Set 6a Laser Diodes 1 Semiconductor Lasers The simplest laser of all. 2014, Henry Zmuda Set 6a Laser Diodes 2 Semiconductor Lasers 1. Homojunction

More information

The discussion about p-n junctions in the semiconductor device is fundamental both

The discussion about p-n junctions in the semiconductor device is fundamental both CHAPTER II MATERIALS JUNCTIONS 2.1 p-n Junctions 2.1.1 Homojunction The discussion about p-n junctions in the semiconductor device is fundamental both in modern electronic applications and in understanding

More information

1. Binary III-V compounds 2 p From which atoms are the 16 binary III-V compounds formed?...column III B, Al, Ga and In...column V N, P, As and Sb...

1. Binary III-V compounds 2 p From which atoms are the 16 binary III-V compounds formed?...column III B, Al, Ga and In...column V N, P, As and Sb... PROBLEMS part B, Semiconductor Materials. 2006 1. Binary III-V compounds 2 p From which atoms are the 16 binary III-V compounds formed?...column III B, Al, Ga and In...column V N, P, As and Sb... 2. Semiconductors

More information

Typical example of the FET: MEtal Semiconductor FET (MESFET)

Typical example of the FET: MEtal Semiconductor FET (MESFET) Typical example of the FET: MEtal Semiconductor FET (MESFET) Conducting channel (RED) is made of highly doped material. The electron concentration in the channel n = the donor impurity concentration N

More information

Lecture 7 PN Junction and MOS Electrostatics(IV) Metal Oxide Semiconductor Structure (contd.)

Lecture 7 PN Junction and MOS Electrostatics(IV) Metal Oxide Semiconductor Structure (contd.) Lecture 7 PN Junction and MOS Electrostatics(IV) Metal Oxide Semiconductor Structure (contd.) Outline 1. Overview of MOS electrostatics under bias 2. Depletion regime 3. Flatband 4. Accumulation regime

More information

Photonic Devices. Light absorption and emission. Transitions between discrete states

Photonic Devices. Light absorption and emission. Transitions between discrete states Light absorption and emission Photonic Devices Transitions between discrete states Transition rate determined by the two states: Fermi s golden rule Absorption and emission of a semiconductor Vertical

More information

BJT - Mode of Operations

BJT - Mode of Operations JT - Mode of Operations JTs can be modeled by two back-to-back diodes. N+ P N- N+ JTs are operated in four modes. HO #6: LN 251 - JT M Models Page 1 1) Forward active / normal junction forward biased junction

More information

ELEC 3908, Physical Electronics, Lecture 18. The Early Effect, Breakdown and Self-Heating

ELEC 3908, Physical Electronics, Lecture 18. The Early Effect, Breakdown and Self-Heating ELEC 3908, Physical Electronics, Lecture 18 The Early Effect, Breakdown and Self-Heating Lecture Outline Previous 2 lectures analyzed fundamental static (dc) carrier transport in the bipolar transistor

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

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

CME 300 Properties of Materials. ANSWERS: Homework 9 November 26, As atoms approach each other in the solid state the quantized energy states:

CME 300 Properties of Materials. ANSWERS: Homework 9 November 26, As atoms approach each other in the solid state the quantized energy states: CME 300 Properties of Materials ANSWERS: Homework 9 November 26, 2011 As atoms approach each other in the solid state the quantized energy states: are split. This splitting is associated with the wave

More information

Lecture 4 - PN Junction and MOS Electrostatics (I) Semiconductor Electrostatics in Thermal Equilibrium September 20, 2005

Lecture 4 - PN Junction and MOS Electrostatics (I) Semiconductor Electrostatics in Thermal Equilibrium September 20, 2005 6.012 - Microelectronic Devices and Circuits - Fall 2005 Lecture 4-1 Contents: Lecture 4 - PN Junction and MOS Electrostatics (I) Semiconductor Electrostatics in Thermal Equilibrium September 20, 2005

More information

( )! N D ( x) ) and equilibrium

( )! N D ( x) ) and equilibrium ECE 66: SOLUTIONS: ECE 66 Homework Week 8 Mark Lundstrom March 7, 13 1) The doping profile for an n- type silicon wafer ( N D = 1 15 cm - 3 ) with a heavily doped thin layer at the surface (surface concentration,

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

Recitation 17: BJT-Basic Operation in FAR

Recitation 17: BJT-Basic Operation in FAR Recitation 17: BJT-Basic Operation in FAR BJT stands for Bipolar Junction Transistor 1. Can be thought of as two p-n junctions back to back, you can have pnp or npn. In analogy to MOSFET small current

More information

Solid State Physics SEMICONDUCTORS - IV. Lecture 25. A.H. Harker. Physics and Astronomy UCL

Solid State Physics SEMICONDUCTORS - IV. Lecture 25. A.H. Harker. Physics and Astronomy UCL Solid State Physics SEMICONDUCTORS - IV Lecture 25 A.H. Harker Physics and Astronomy UCL 9.9 Carrier diffusion and recombination Suppose we have a p-type semiconductor, i.e. n h >> n e. (1) Create a local

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

Chapter 5. Semiconductor Laser

Chapter 5. Semiconductor Laser Chapter 5 Semiconductor Laser 5.0 Introduction Laser is an acronym for light amplification by stimulated emission of radiation. Albert Einstein in 1917 showed that the process of stimulated emission must

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

Semiconductor Integrated Process Design (MS 635)

Semiconductor Integrated Process Design (MS 635) Semiconductor Integrated Process Design (MS 635) Instructor: Prof. Keon Jae Lee - Office: 응용공학동 #4306, Tel: #3343 - Email: keonlee@kaist.ac.kr Lecture: (Tu, Th), 1:00-2:15 #2425 Office hour: Tues & Thur

More information

Lecture 8 - Carrier Drift and Diffusion (cont.), Carrier Flow. February 21, 2007

Lecture 8 - Carrier Drift and Diffusion (cont.), Carrier Flow. February 21, 2007 6.720J/3.43J - Integrated Microelectronic Devices - Spring 2007 Lecture 8-1 Lecture 8 - Carrier Drift and Diffusion (cont.), Carrier Flow February 21, 2007 Contents: 1. Quasi-Fermi levels 2. Continuity

More information

Sheng S. Li. Semiconductor Physical Electronics. Second Edition. With 230 Figures. 4) Springer

Sheng S. Li. Semiconductor Physical Electronics. Second Edition. With 230 Figures. 4) Springer Sheng S. Li Semiconductor Physical Electronics Second Edition With 230 Figures 4) Springer Contents Preface 1. Classification of Solids and Crystal Structure 1 1.1 Introduction 1 1.2 The Bravais Lattice

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

- 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

Lecture 16 - The pn Junction Diode (II) Equivalent Circuit Model. April 8, 2003

Lecture 16 - The pn Junction Diode (II) Equivalent Circuit Model. April 8, 2003 6.012 - Microelectronic Devices and Circuits - Spring 2003 Lecture 16-1 Lecture 16 - The pn Junction Diode (II) Equivalent Circuit Model April 8, 2003 Contents: 1. I-V characteristics (cont.) 2. Small-signal

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

Lecture 4 - PN Junction and MOS Electrostatics (I) Semiconductor Electrostatics in Thermal Equilibrium. February 13, 2003

Lecture 4 - PN Junction and MOS Electrostatics (I) Semiconductor Electrostatics in Thermal Equilibrium. February 13, 2003 6.012 - Microelectronic Devices and Circuits - Spring 2003 Lecture 4-1 Contents: Lecture 4 - PN Junction and MOS Electrostatics (I) Semiconductor Electrostatics in Thermal Equilibrium February 13, 2003

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

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

Lecture 8 PN Junction and MOS Electrostatics (V) Electrostatics of Metal Oxide Semiconductor Structure (cont.) October 4, 2005

Lecture 8 PN Junction and MOS Electrostatics (V) Electrostatics of Metal Oxide Semiconductor Structure (cont.) October 4, 2005 6.12 Microelectronic Devices and Circuits Fall 25 Lecture 8 1 Lecture 8 PN Junction and MOS Electrostatics (V) Electrostatics of Metal Oide Semiconductor Structure (cont.) Contents: October 4, 25 1. Overview

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

Lecture 9 - Carrier Drift and Diffusion (cont.), Carrier Flow. September 24, 2001

Lecture 9 - Carrier Drift and Diffusion (cont.), Carrier Flow. September 24, 2001 6.720J/3.43J - Integrated Microelectronic Devices - Fall 2001 Lecture 9-1 Lecture 9 - Carrier Drift and Diffusion (cont.), Carrier Flow September 24, 2001 Contents: 1. Quasi-Fermi levels 2. Continuity

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

The Devices: MOS Transistors

The Devices: MOS Transistors The Devices: MOS Transistors References: Semiconductor Device Fundamentals, R. F. Pierret, Addison-Wesley Digital Integrated Circuits: A Design Perspective, J. Rabaey et.al. Prentice Hall NMOS Transistor

More information

MSE 310/ECE 340: Electrical Properties of Materials Fall 2014 Department of Materials Science and Engineering Boise State University

MSE 310/ECE 340: Electrical Properties of Materials Fall 2014 Department of Materials Science and Engineering Boise State University MSE 310/ECE 340: Electrical Properties of Materials Fall 2014 Department of Materials Science and Engineering Boise State University Practice Final Exam 1 Read the questions carefully Label all figures

More information

Chapter 1 Overview of Semiconductor Materials and Physics

Chapter 1 Overview of Semiconductor Materials and Physics Chapter 1 Overview of Semiconductor Materials and Physics Professor Paul K. Chu Conductivity / Resistivity of Insulators, Semiconductors, and Conductors Semiconductor Elements Period II III IV V VI 2 B

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

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

Lecture 8 - Carrier Drift and Diffusion (cont.) September 21, 2001

Lecture 8 - Carrier Drift and Diffusion (cont.) September 21, 2001 6.720J/3.43J - Integrated Microelectronic Devices - Fall 2001 Lecture 8-1 Lecture 8 - Carrier Drift and Diffusion (cont.) September 21, 2001 Contents: 1. Non-uniformly doped semiconductor in thermal equilibrium

More information

Course overview. Me: Dr Luke Wilson. The course: Physics and applications of semiconductors. Office: E17 open door policy

Course overview. Me: Dr Luke Wilson. The course: Physics and applications of semiconductors. Office: E17 open door policy Course overview Me: Dr Luke Wilson Office: E17 open door policy email: luke.wilson@sheffield.ac.uk The course: Physics and applications of semiconductors 10 lectures aim is to allow time for at least one

More information

Physics of Semiconductors

Physics of Semiconductors Physics of Semiconductors 9 th 2016.6.13 Shingo Katsumoto Department of Physics and Institute for Solid State Physics University of Tokyo Site for uploading answer sheet Outline today Answer to the question

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