Lecture 2. Semiconductor Physics. Sunday 4/10/2015 Semiconductor Physics 1-1

Size: px
Start display at page:

Download "Lecture 2. Semiconductor Physics. Sunday 4/10/2015 Semiconductor Physics 1-1"

Transcription

1 Lecture 2 Semiconductor Physics Sunday 4/10/2015 Semiconductor Physics 1-1

2 Outline Intrinsic bond model: electrons and holes Charge carrier generation and recombination Intrinsic semiconductor Doping: Extrinsic semiconductor Charge Neutrality Introduction to Charge Carrier Transport Semiconductor Physics 1-2

3 Test Yourself 1. Can you differentiate between: Semiconductors Conductors Insulators 2. What is the difference between charge carriers and free charge carriers? Semiconductor Physics 1-3

4 Semiconductor Materials Three most used semiconductors: carbon (C), silicon (Si) and germanium (Ge) Carbon Silicon Germanium Semiconductor Physics 1-4

5 Silicon (most common semiconductor material) Bond Model Si in Column IV of the periodic table Electronic structure of silicon atom: 10 core electrons (tightly bound) 4 valence electrons (loosely bound, responsible for most of the chemical properties Other semiconductors: Single crystal: Ge, C (diamond form) Compound: GaAs, InP, InGaAs, InGaAsP, ZnSe, CdTe (on the average, 4 valence electrons per atom) Semiconductor Physics 1-5

6 Silicon crystal structure Diamond lattice: atoms tetrahedrally bonded by sharing valence electrons covalent bonding Each atom shares 4 electrons low energy situation Si atomic density: 5 x atoms/cm 3 Semiconductor Physics 1-6

7 Simple flattened model of Si crystal At 0 o K: All bonds are satisfied (all valence electrons engaged in bonding) No free electrons (or holes) This bonding of atoms, strengthened by the sharing of electrons, is called covalent bonding Molecules or ions tend to be most stable when the outermost electron shells of their constituent atoms contain eight electrons Semiconductor Physics 1-7

8 Creation of electron-hole pair At room temperature (default 27 o C or 300 o K), approximately 1.5X free carriers in 1 cm 3 of intrinsic silicon material Intrinsic semiconductor material means material has been refined to a very low level of impurities. Semiconductor Physics 1-8

9 Creation of electron-hole pair Electron-hole pairs in a silicon crystal. Free electrons are being generated continuously while some recombine with holes Electrons and holes in semiconductors are fuzzier : they span many atomic sites At finite temperature, some bonds are broken free electrons Mobile negative charge -1.6 x C free holes Mobile positive charge, +1.6 x C Semiconductor Physics 1-9

10 Definitions electron means free electron Not concerned with bonding electrons or core electrons Define: n (free) electron concentration [cm -3 ] p hole concentration [cm -3 ] Law of Mass Action (at thermal equilibrium) n 2 n. i Where n i intrinsic carrier concentration [cm 3 ] p Semiconductor Physics 1-10

11 Generation and Recombination Generation: break-up of covalent bond to form electron and hole pairs In an intrinsic semiconductor the number of holes is equal to the number of free electrons Generate new hole-electron pairs per unit volume per second requires energy from thermal or optical sources Generation rate: G = G(th) + G opt +. [cm 3. s 1 ] Recombination: formation of covalent bond by bringing together electron and hole Releases energy in thermal or optical form Recombination rate R [cm 3. s 1 ] 1 recombination event requires 1 electron + 1 hole On an average, a hole (an electron) will exist for ζ p (ζ n ) seconds before recombination. This time is called the mean lifetime of the hole (electron) Semiconductor Physics 1-11

12 Intrinsic Semiconductors Thermal Equilibrium where Steady state plus absence of external energy sources With increasing temperature, the density of holeelectron pairs (free charge carriers) increases in an intrinsic semiconductor. n 2 i AT 3 e E kt n i intrinsic carrier concentration [cm 3 ] E G0 is the energy gap (the energy required to break a covalent bond) at 0 o K k is the Boltzmann constant in electron volts per degree kelvin (J/K) [k = 1.38x10-23 J/K] A is a material-dependent constant independent of T Semiconductor Physics 1-12 G 0

13 Intrinsic Semiconductors In Si at 300 o K ( room temperature ): ni 1x10 10 cm -3 In a sufficiently pure Si wafer at 300 o K ( intrinsic semiconductor): n = p = n i cm 3 n i is a very strong function of temperature T n i Semiconductor Physics 1-13

14 Effect of Temperature on Conductivity Conductor increase resistance with increase in heat ( number of carrier do not increase) have a positive temperature coefficient w.r.t. resistance Semiconductor increase conductivity with increase in heat ( number of carrier increase) have a negative temperature coefficient w.r.t. resistance Semiconductor Physics 1-14

15 Controlling the properties of a Semiconductor Doping = engineered introduction of foreign atoms to modify semiconductor electrical properties Doping is the process of deliberately adding impurities to the crystal during manufacturing and increases the number of current carries (electrons or holes) Impurities (extraneous elements) Doping process create n-type and p-type of semiconductors A semiconductor material that has been subjected to the doping process is called an extrinsic material Semiconductor Physics 1-15

16 Doping Silicon: 4 valence electrons Each Si atom bonds to four others Replace some Si atoms with atoms that do not have four valence electrons These atoms will have: - an extra electron (group V) Donors - an extra hole (group III) Acceptors Doping increases the number of carriers Semiconductor Physics 1-16

17 Donors Introduce electrons to semiconductors (but not holes) For Si, group V elements (dopants) with 5 valence electrons (Arsenic As, phosphorus P, antimony Sb ) Semiconductor Physics 1-17

18 Donors Four of five electrons participate in bonding The 5 th electron easy to release at room temperature, each donor releases 1 electron that is available for conduction Donor site become positively charged (fixed charge) Define: N d donor concentration [cm -3 ] If N d << n i doping is irrelevant Intrinsic semiconductor n = p = n i If N d >> n i, doping controls carrier concentration Extrinsic semiconductor n = N d and p = n i2 / N d Note: n >> p : n-type semiconductor In general: N d cm -3 Semiconductor Physics 1-18

19 Acceptors Introduce holes to semiconductors (but not electrons) For Si, group III elements with 3 valence electrons (usually Boron(B), Gallium (Ga) and Indium (In)) Semiconductor Physics 1-19

20 Acceptors Three electrons participate in bonding One bonding site unsatisfied making it easy to accept neighboring bonding electron to complete all bonds at room temperature, each acceptor releases hole that is available for conduction Acceptor site becomes negatively charged (fixed charge) Semiconductor Physics 1-20

21 Acceptors Define: Na acceptor concentration [cm -3 ] If N a << n i doping is irrelevant Intrinsic semiconductor n = p = n i If N a >> n i, doping controls carrier concentration Extrinsic semiconductor p = N a and n = n i2 / N a Note: p >> n : p-type semiconductor In general: N a cm -3 Semiconductor Physics 1-21

22 Summary of Charge Carriers Semiconductor Physics 1-22

23 Majority and Minority Carriers n-type material, the electron is called majority carrier and hole the minority carrier p-type material, the hole is called majority carrier and electron the minority carrier Semiconductor Physics 1-23

24 Charge Neutrality The semiconductor remains charge neutral even when it has been doped Overall charge neutrality must be satisfied In general: the net charge density ρ (C/cm 3 ) in a + semiconductor = ρ = q (p n + N d N a ) Where q: electric (elementary) charge = 1.6 Х C Semiconductor Physics 1-24

25 Charge Neutrality Example Let us examine this for: N d = cm -3, Na = 0 Then, n = N d = cm 3, p = n i2 /N d = 10 3 cm 3 Using the equation ρ = q (p n + N d N a ), we find that ρ 0!! What is wrong?? Semiconductor Physics 1-25

26 Charge Neutrality Nothing wrong! We just made the approximation when we assumed that n = N d We should really solve the following system of equations (for N a =0): p n + N d = 0 n.p = n i 2 n 2 - n. N d - n i 2 = 0 n N d Semiconductor Physics 1-26

27 Charge Carrier Transport Any motion of free carriers in a semiconductor leads to a current Different causes for having motion Associated random motion due to the thermal energy (Thermal Motion) Motion can be caused by an electric field due to an externally applied voltage (Carrier Drift) Motion from regions where the carrier density is high to regions where the carrier density is low (Carrier Diffusion) Semiconductor Physics 1-27

28 Thermal Motion In thermal equilibrium, carriers are not sitting still: Undergo collisions with vibrating Si atoms (Brownian motion) Electrostatically interact with each other and with ionized (charged) dopants Semiconductor Physics 1-28

29 Thermal Motion (cont d) Characteristic time constant of thermal motion mean free time between collisions T c Collison time (seconds) In between collisions, carriers acquire high velocity: v th thermal velocity (cm/second) Characteristic length of thermal motion: λ mean free path [cm] = v th T c Example: For Si at room temperature (27 o C or 300 o K), we have the following numbers T c seconds, v th 10 7 cm/second λ 0.01 μm Carriers undergo many collisions as they travel through devices Semiconductor Physics 1-29

30 Lecture Summary Covered material Continue Semiconductor Materials Types of semiconductors Two types of carriers (mobile charge particles): electrons and holes Creation of electron-hole pairs Doping Donors n-type semiconductor material Acceptors p-type semiconductor material Important equations under thermal equilibrium conditions: (p n + N d N a = 0) and (n.p = n i2 ) Material to be covered next lecture Continue Semiconductor Physics Carrier Transport (Carrier Drift and Carrier Diffusion) pn junctions (or diodes) Basics Semiconductor Physics 1-30

Lecture 1. OUTLINE Basic Semiconductor Physics. Reading: Chapter 2.1. Semiconductors Intrinsic (undoped) silicon Doping Carrier concentrations

Lecture 1. OUTLINE Basic Semiconductor Physics. Reading: Chapter 2.1. Semiconductors Intrinsic (undoped) silicon Doping Carrier concentrations Lecture 1 OUTLINE Basic Semiconductor Physics Semiconductors Intrinsic (undoped) silicon Doping Carrier concentrations Reading: Chapter 2.1 EE105 Fall 2007 Lecture 1, Slide 1 What is a Semiconductor? Low

More information

Semiconductor physics I. The Crystal Structure of Solids

Semiconductor physics I. The Crystal Structure of Solids Lecture 3 Semiconductor physics I The Crystal Structure of Solids 1 Semiconductor materials Types of solids Space lattices Atomic Bonding Imperfection and doping in SOLIDS 2 Semiconductor Semiconductors

More information

Atoms? All matters on earth made of atoms (made up of elements or combination of elements).

Atoms? All matters on earth made of atoms (made up of elements or combination of elements). Chapter 1 Atoms? All matters on earth made of atoms (made up of elements or combination of elements). Atomic Structure Atom is the smallest particle of an element that can exist in a stable or independent

More information

Engineering 2000 Chapter 8 Semiconductors. ENG2000: R.I. Hornsey Semi: 1

Engineering 2000 Chapter 8 Semiconductors. ENG2000: R.I. Hornsey Semi: 1 Engineering 2000 Chapter 8 Semiconductors ENG2000: R.I. Hornsey Semi: 1 Overview We need to know the electrical properties of Si To do this, we must also draw on some of the physical properties and we

More information

ECE 335: Electronic Engineering Lecture 2: Semiconductors

ECE 335: Electronic Engineering Lecture 2: Semiconductors Faculty of Engineering ECE 335: Electronic Engineering Lecture 2: Semiconductors Agenda Intrinsic Semiconductors Extrinsic Semiconductors N-type P-type Carrier Transport Drift Diffusion Semiconductors

More information

ECE 250 Electronic Devices 1. Electronic Device Modeling

ECE 250 Electronic Devices 1. Electronic Device Modeling ECE 250 Electronic Devices 1 ECE 250 Electronic Device Modeling ECE 250 Electronic Devices 2 Introduction to Semiconductor Physics You should really take a semiconductor device physics course. We can only

More information

ELECTRONIC I Lecture 1 Introduction to semiconductor. By Asst. Prof Dr. Jassim K. Hmood

ELECTRONIC I Lecture 1 Introduction to semiconductor. By Asst. Prof Dr. Jassim K. Hmood ELECTRONIC I Lecture 1 Introduction to semiconductor By Asst. Prof Dr. Jassim K. Hmood SOLID-STATE ELECTRONIC MATERIALS Electronic materials generally can be divided into three categories: insulators,

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

A semiconductor is an almost insulating material, in which by contamination (doping) positive or negative charge carriers can be introduced.

A semiconductor is an almost insulating material, in which by contamination (doping) positive or negative charge carriers can be introduced. Semiconductor A semiconductor is an almost insulating material, in which by contamination (doping) positive or negative charge carriers can be introduced. Page 2 Semiconductor materials Page 3 Energy levels

More information

Introduction to Semiconductor Physics. Prof.P. Ravindran, Department of Physics, Central University of Tamil Nadu, India

Introduction to Semiconductor Physics. Prof.P. Ravindran, Department of Physics, Central University of Tamil Nadu, India Introduction to Semiconductor Physics 1 Prof.P. Ravindran, Department of Physics, Central University of Tamil Nadu, India http://folk.uio.no/ravi/cmp2013 Review of Semiconductor Physics Semiconductor fundamentals

More information

ELECTRONIC DEVICES AND CIRCUITS SUMMARY

ELECTRONIC DEVICES AND CIRCUITS SUMMARY ELECTRONIC DEVICES AND CIRCUITS SUMMARY Classification of Materials: Insulator: An insulator is a material that offers a very low level (or negligible) of conductivity when voltage is applied. Eg: Paper,

More information

EECS130 Integrated Circuit Devices

EECS130 Integrated Circuit Devices EECS130 Integrated Circuit Devices Professor Ali Javey 8/30/2007 Semiconductor Fundamentals Lecture 2 Read: Chapters 1 and 2 Last Lecture: Energy Band Diagram Conduction band E c E g Band gap E v Valence

More information

CLASS 12th. Semiconductors

CLASS 12th. Semiconductors CLASS 12th Semiconductors 01. Distinction Between Metals, Insulators and Semi-Conductors Metals are good conductors of electricity, insulators do not conduct electricity, while the semiconductors have

More information

ECE 142: Electronic Circuits Lecture 3: Semiconductors

ECE 142: Electronic Circuits Lecture 3: Semiconductors Faculty of Engineering ECE 142: Electronic Circuits Lecture 3: Semiconductors Agenda Intrinsic Semiconductors Extrinsic Semiconductors N-type P-type Carrier Transport Drift Diffusion Semiconductors A semiconductor

More information

EE301 Electronics I , Fall

EE301 Electronics I , Fall EE301 Electronics I 2018-2019, Fall 1. Introduction to Microelectronics (1 Week/3 Hrs.) Introduction, Historical Background, Basic Consepts 2. Rewiev of Semiconductors (1 Week/3 Hrs.) Semiconductor materials

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

EECS143 Microfabrication Technology

EECS143 Microfabrication Technology EECS143 Microfabrication Technology Professor Ali Javey Introduction to Materials Lecture 1 Evolution of Devices Yesterday s Transistor (1947) Today s Transistor (2006) Why Semiconductors? Conductors e.g

More information

Basic Semiconductor Physics

Basic Semiconductor Physics 6 Basic Semiconductor Physics 6.1 Introduction With this chapter we start with the discussion of some important concepts from semiconductor physics, which are required to understand the operation of solar

More information

Lecture 2 Electrons and Holes in Semiconductors

Lecture 2 Electrons and Holes in Semiconductors EE 471: Transport Phenomena in Solid State Devices Spring 2018 Lecture 2 Electrons and Holes in Semiconductors Bryan Ackland Department of Electrical and Computer Engineering Stevens Institute of Technology

More information

Electro - Principles I

Electro - Principles I Electro - Principles I Page 10-1 Atomic Theory It is necessary to know what goes on at the atomic level of a semiconductor so the characteristics of the semiconductor can be understood. In many cases a

More information

SEMICONDUCTORS. Conductivity lies between conductors and insulators. The flow of charge in a metal results from the

SEMICONDUCTORS. Conductivity lies between conductors and insulators. The flow of charge in a metal results from the SEMICONDUCTORS Conductivity lies between conductors and insulators The flow of charge in a metal results from the movement of electrons Electros are negatively charged particles (q=1.60x10-19 C ) The outermost

More information

Semiconductors 1. Explain different types of semiconductors in detail with necessary bond diagrams. Intrinsic semiconductors:

Semiconductors 1. Explain different types of semiconductors in detail with necessary bond diagrams. Intrinsic semiconductors: Semiconductors 1. Explain different types of semiconductors in detail with necessary bond diagrams. There are two types of semi conductors. 1. Intrinsic semiconductors 2. Extrinsic semiconductors Intrinsic

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

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

electronics fundamentals

electronics fundamentals electronics fundamentals circuits, devices, and applications THOMAS L. FLOYD DAVID M. BUCHLA Lesson 1: Diodes and Applications Semiconductors Figure 1-1 The Bohr model of an atom showing electrons in orbits

More information

ECE 442. Spring, Lecture -2

ECE 442. Spring, Lecture -2 ECE 442 Power Semiconductor Devices and Integrated circuits Spring, 2006 University of Illinois at Chicago Lecture -2 Semiconductor physics band structures and charge carriers 1. What are the types of

More information

ITT Technical Institute ET215 Devices I Unit 1

ITT Technical Institute ET215 Devices I Unit 1 ITT Technical Institute ET215 Devices I Unit 1 Chapter 1 Chapter 2, Sections 2.1-2.4 Chapter 1 Basic Concepts of Analog Circuits Recall ET115 & ET145 Ohms Law I = V/R If voltage across a resistor increases

More information

Unit IV Semiconductors Engineering Physics

Unit IV Semiconductors Engineering Physics Introduction A semiconductor is a material that has a resistivity lies between that of a conductor and an insulator. The conductivity of a semiconductor material can be varied under an external electrical

More information

KATIHAL FİZİĞİ MNT-510

KATIHAL FİZİĞİ MNT-510 KATIHAL FİZİĞİ MNT-510 YARIİLETKENLER Kaynaklar: Katıhal Fiziği, Prof. Dr. Mustafa Dikici, Seçkin Yayıncılık Katıhal Fiziği, Şakir Aydoğan, Nobel Yayıncılık, Physics for Computer Science Students: With

More information

Key Questions. ECE 340 Lecture 6 : Intrinsic and Extrinsic Material I 9/10/12. Class Outline: Effective Mass Intrinsic Material

Key Questions. ECE 340 Lecture 6 : Intrinsic and Extrinsic Material I 9/10/12. Class Outline: Effective Mass Intrinsic Material 9/1/1 ECE 34 Lecture 6 : Intrinsic and Extrinsic Material I Class Outline: Things you should know when you leave Key Questions What is the physical meaning of the effective mass What does a negative effective

More information

collisions of electrons. In semiconductor, in certain temperature ranges the conductivity increases rapidly by increasing temperature

collisions of electrons. In semiconductor, in certain temperature ranges the conductivity increases rapidly by increasing temperature 1.9. Temperature Dependence of Semiconductor Conductivity Such dependence is one most important in semiconductor. In metals, Conductivity decreases by increasing temperature due to greater frequency of

More information

Lecture 3b. Bonding Model and Dopants. Reading: (Cont d) Notes and Anderson 2 sections

Lecture 3b. Bonding Model and Dopants. Reading: (Cont d) Notes and Anderson 2 sections Lecture 3b Bonding Model and Dopants Reading: (Cont d) Notes and Anderson 2 sections 2.3-2.7 The need for more control over carrier concentration Without help the total number of carriers (electrons and

More information

Semiconductors. Semiconductors also can collect and generate photons, so they are important in optoelectronic or photonic applications.

Semiconductors. Semiconductors also can collect and generate photons, so they are important in optoelectronic or photonic applications. Semiconductors Semiconducting materials have electrical properties that fall between true conductors, (like metals) which are always highly conducting and insulators (like glass or plastic or common ceramics)

More information

EE143 Fall 2016 Microfabrication Technologies. Evolution of Devices

EE143 Fall 2016 Microfabrication Technologies. Evolution of Devices EE143 Fall 2016 Microfabrication Technologies Prof. Ming C. Wu wu@eecs.berkeley.edu 511 Sutardja Dai Hall (SDH) 1-1 Evolution of Devices Yesterday s Transistor (1947) Today s Transistor (2006) 1-2 1 Why

More information

Semiconductor Device Physics

Semiconductor Device Physics 1 Semiconductor Device Physics Lecture 1 http://zitompul.wordpress.com 2 0 1 3 2 Semiconductor Device Physics Textbook: Semiconductor Device Fundamentals, Robert F. Pierret, International Edition, Addison

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

Review of Semiconductor Fundamentals

Review of Semiconductor Fundamentals ECE 541/ME 541 Microelectronic Fabrication Techniques Review of Semiconductor Fundamentals Zheng Yang (ERF 3017, email: yangzhen@uic.edu) Page 1 Semiconductor A semiconductor is an almost insulating material,

More information

SEMICONDUCTOR PHYSICS

SEMICONDUCTOR PHYSICS SEMICONDUCTOR PHYSICS by Dibyendu Chowdhury Semiconductors The materials whose electrical conductivity lies between those of conductors and insulators, are known as semiconductors. Silicon Germanium Cadmium

More information

Introduction to Engineering Materials ENGR2000. Dr.Coates

Introduction to Engineering Materials ENGR2000. Dr.Coates Introduction to Engineering Materials ENGR2000 Chapter 18: Electrical Properties Dr.Coates 18.2 Ohm s Law V = IR where R is the resistance of the material, V is the voltage and I is the current. l R A

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

EE 446/646 Photovoltaic Devices I. Y. Baghzouz

EE 446/646 Photovoltaic Devices I. Y. Baghzouz EE 446/646 Photovoltaic Devices I Y. Baghzouz What is Photovoltaics? First used in about 1890, the word has two parts: photo, derived from the Greek word for light, volt, relating to electricity pioneer

More information

3C3 Analogue Circuits

3C3 Analogue Circuits Department of Electronic & Electrical Engineering Trinity College Dublin, 2014 3C3 Analogue Circuits Prof J K Vij jvij@tcd.ie Lecture 1: Introduction/ Semiconductors & Doping 1 Course Outline (subject

More information

ESE 372 / Spring 2013 / Lecture 5 Metal Oxide Semiconductor Field Effect Transistor

ESE 372 / Spring 2013 / Lecture 5 Metal Oxide Semiconductor Field Effect Transistor Metal Oxide Semiconductor Field Effect Transistor V G V G 1 Metal Oxide Semiconductor Field Effect Transistor We will need to understand how this current flows through Si What is electric current? 2 Back

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

CLASS 1 & 2 REVISION ON SEMICONDUCTOR PHYSICS. Reference: Electronic Devices by Floyd

CLASS 1 & 2 REVISION ON SEMICONDUCTOR PHYSICS. Reference: Electronic Devices by Floyd CLASS 1 & 2 REVISION ON SEMICONDUCTOR PHYSICS Reference: Electronic Devices by Floyd 1 ELECTRONIC DEVICES Diodes, transistors and integrated circuits (IC) are typical devices in electronic circuits. All

More information

ECE 340 Lecture 6 : Intrinsic and Extrinsic Material I Class Outline:

ECE 340 Lecture 6 : Intrinsic and Extrinsic Material I Class Outline: ECE 340 Lecture 6 : Intrinsic and Extrinsic Material I Class Outline: Effective Mass Intrinsic Material Extrinsic Material Things you should know when you leave Key Questions What is the physical meaning

More information

First-Hand Investigation: Modeling of Semiconductors

First-Hand Investigation: Modeling of Semiconductors perform an investigation to model the behaviour of semiconductors, including the creation of a hole or positive charge on the atom that has lost the electron and the movement of electrons and holes in

More information

Ch. 2: Energy Bands And Charge Carriers In Semiconductors

Ch. 2: Energy Bands And Charge Carriers In Semiconductors Ch. 2: Energy Bands And Charge Carriers In Semiconductors Discrete energy levels arise from balance of attraction force between electrons and nucleus and repulsion force between electrons each electron

More information

Chemistry Instrumental Analysis Lecture 8. Chem 4631

Chemistry Instrumental Analysis Lecture 8. Chem 4631 Chemistry 4631 Instrumental Analysis Lecture 8 UV to IR Components of Optical Basic components of spectroscopic instruments: stable source of radiant energy transparent container to hold sample device

More information

Electrical Resistance

Electrical Resistance Electrical Resistance I + V _ W Material with resistivity ρ t L Resistance R V I = L ρ Wt (Unit: ohms) where ρ is the electrical resistivity 1 Adding parts/billion to parts/thousand of dopants to pure

More information

Carriers Concentration, Current & Hall Effect in Semiconductors. Prof.P. Ravindran, Department of Physics, Central University of Tamil Nadu, India

Carriers Concentration, Current & Hall Effect in Semiconductors. Prof.P. Ravindran, Department of Physics, Central University of Tamil Nadu, India Carriers Concentration, Current & Hall Effect in Semiconductors 1 Prof.P. Ravindran, Department of Physics, Central University of Tamil Nadu, India http://folk.uio.no/ravi/semi2013 Conductivity Charge

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

Charge Carriers in Semiconductor

Charge Carriers in Semiconductor Charge Carriers in Semiconductor To understand PN junction s IV characteristics, it is important to understand charge carriers behavior in solids, how to modify carrier densities, and different mechanisms

More information

Chapter 1 Semiconductor basics

Chapter 1 Semiconductor basics Chapter 1 Semiconductor basics ELEC-H402/CH1: Semiconductor basics 1 Basic semiconductor concepts Semiconductor basics Semiconductors, silicon and hole-electron pair Intrinsic silicon properties Doped

More information

Quiz #1 Practice Problem Set

Quiz #1 Practice Problem Set Name: Student Number: ELEC 3908 Physical Electronics Quiz #1 Practice Problem Set? Minutes January 22, 2016 - No aids except a non-programmable calculator - All questions must be answered - All questions

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

The Periodic Table III IV V

The Periodic Table III IV V The Periodic Table III IV V Slide 1 Electronic Bonds in Silicon 2-D picture of perfect crystal of pure silicon; double line is a Si-Si bond with each line representing an electron Si ion (charge +4 q)

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. 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 3 Semiconductor Physics (II) Carrier Transport

Lecture 3 Semiconductor Physics (II) Carrier Transport Lecture 3 Semiconductor Physics (II) Carrier Transport Thermal Motion Carrier Drift Carrier Diffusion Outline Reading Assignment: Howe and Sodini; Chapter 2, Sect. 2.4-2.6 6.012 Spring 2009 Lecture 3 1

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

Ga and P Atoms to Covalent Solid GaP

Ga and P Atoms to Covalent Solid GaP Ga and P Atoms to Covalent Solid GaP Band Gaps in Binary Group III-V Semiconductors Mixed Semiconductors Affect of replacing some of the As with P in GaAs Band Gap (ev) (nm) GaAs 1.35 919 (IR) GaP 2.24

More information

Semiconductors (Chất1bán1dẫn)

Semiconductors (Chất1bán1dẫn) To describe the properties of n-type and p-type semiconductors and how a pn jun formed To study a diode and the characteristics of diode 1-1 Atomic Structure Atomic1Structure An atom is the smallest particle

More information

Processing of Semiconducting Materials Prof. Pallab Banerji Department of Material Science Indian Institute of Technology, Kharagpur

Processing of Semiconducting Materials Prof. Pallab Banerji Department of Material Science Indian Institute of Technology, Kharagpur Processing of Semiconducting Materials Prof. Pallab Banerji Department of Material Science Indian Institute of Technology, Kharagpur Lecture - 4 Doping in Semiconductors Good morning. Let us start with

More information

Basic cell design. Si cell

Basic cell design. Si cell Basic cell design Si cell 1 Concepts needed to describe photovoltaic device 1. energy bands in semiconductors: from bonds to bands 2. free carriers: holes and electrons, doping 3. electron and hole current:

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

3.1 Introduction to Semiconductors. Y. Baghzouz ECE Department UNLV

3.1 Introduction to Semiconductors. Y. Baghzouz ECE Department UNLV 3.1 Introduction to Semiconductors Y. Baghzouz ECE Department UNLV Introduction In this lecture, we will cover the basic aspects of semiconductor materials, and the physical mechanisms which are at the

More information

Diamond. Covalent Insulators and Semiconductors. Silicon, Germanium, Gray Tin. Chem 462 September 24, 2004

Diamond. Covalent Insulators and Semiconductors. Silicon, Germanium, Gray Tin. Chem 462 September 24, 2004 Covalent Insulators and Chem 462 September 24, 2004 Diamond Pure sp 3 carbon All bonds staggered- ideal d(c-c) - 1.54 Å, like ethane Silicon, Germanium, Gray Tin Diamond structure Si and Ge: semiconductors

More information

EE 346: Semiconductor Devices. 02/08/2017 Tewodros A. Zewde 1

EE 346: Semiconductor Devices. 02/08/2017 Tewodros A. Zewde 1 EE 346: Semiconductor Devices 02/08/2017 Tewodros A. Zewde 1 DOPANT ATOMS AND ENERGY LEVELS Without help the total number of carriers (electrons and holes) is limited to 2ni. For most materials, this is

More information

The photovoltaic effect occurs in semiconductors where there are distinct valence and

The photovoltaic effect occurs in semiconductors where there are distinct valence and How a Photovoltaic Cell Works The photovoltaic effect occurs in semiconductors where there are distinct valence and conduction bands. (There are energies at which electrons can not exist within the solid)

More information

LN 3 IDLE MIND SOLUTIONS

LN 3 IDLE MIND SOLUTIONS IDLE MIND SOLUTIONS 1. Let us first look in most general terms at the optical properties of solids with band gaps (E g ) of less than 4 ev, semiconductors by definition. The band gap energy (E g ) can

More information

The Semiconductor in Equilibrium

The Semiconductor in Equilibrium Lecture 6 Semiconductor physics IV The Semiconductor in Equilibrium Equilibrium, or thermal equilibrium No external forces such as voltages, electric fields. Magnetic fields, or temperature gradients are

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 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

Semiconductor Devices and Circuits Fall Midterm Exam. Instructor: Dr. Dietmar Knipp, Professor of Electrical Engineering. Name: Mat. -Nr.

Semiconductor Devices and Circuits Fall Midterm Exam. Instructor: Dr. Dietmar Knipp, Professor of Electrical Engineering. Name: Mat. -Nr. Semiconductor Devices and Circuits Fall 2003 Midterm Exam Instructor: Dr. Dietmar Knipp, Professor of Electrical Engineering Name: Mat. -Nr.: Guidelines: Duration of the Midterm: 1 hour The exam is a closed

More information

smal band gap Saturday, April 9, 2011

smal band gap Saturday, April 9, 2011 small band gap upper (conduction) band empty small gap valence band filled 2s 2p 2s 2p hybrid (s+p)band 2p no gap 2s (depend on the crystallographic orientation) extrinsic semiconductor semi-metal electron

More information

16EC401 BASIC ELECTRONIC DEVICES UNIT I PN JUNCTION DIODE. Energy Band Diagram of Conductor, Insulator and Semiconductor:

16EC401 BASIC ELECTRONIC DEVICES UNIT I PN JUNCTION DIODE. Energy Band Diagram of Conductor, Insulator and Semiconductor: 16EC401 BASIC ELECTRONIC DEVICES UNIT I PN JUNCTION DIODE Energy bands in Intrinsic and Extrinsic silicon: Energy Band Diagram of Conductor, Insulator and Semiconductor: 1 2 Carrier transport: Any motion

More information

Introduction to Semiconductor Devices

Introduction to Semiconductor Devices Physics 233 Experiment 48 Introduction to Semiconductor Devices References 1. G.W. Neudeck, The PN Junction Diode, Addison-Wesley MA 1989 2. Background notes (Appendix A) 3. Specification sheet for Diode

More information

CEMTool Tutorial. Semiconductor physics

CEMTool Tutorial. Semiconductor physics EMTool Tutorial Semiconductor physics Overview This tutorial is part of the EMWARE series. Each tutorial in this series will teach you a specific topic of common applications by explaining theoretical

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

EXTRINSIC SEMICONDUCTOR

EXTRINSIC SEMICONDUCTOR EXTRINSIC SEMICONDUCTOR EXTRINSIC SEMICONDUCTOR A semiconductor in which the impurity atoms are added by doping process is called Extrinsic semiconductor. The addition of impurities increases the carrier

More information

Introduction to Semiconductor Devices

Introduction to Semiconductor Devices Physics 233 Experiment 48 Introduction to Semiconductor Devices References 1. G.W. Neudeck, The PN Junction Diode, Addison-Wesley MA 1989 2. Background notes (Appendix A) 3. Specification sheet for Diode

More information

Mat E 272 Lecture 25: Electrical properties of materials

Mat E 272 Lecture 25: Electrical properties of materials Mat E 272 Lecture 25: Electrical properties of materials December 6, 2001 Introduction: Calcium and copper are both metals; Ca has a valence of +2 (2 electrons per atom) while Cu has a valence of +1 (1

More information

Semiconductor Devices, Fall Gunnar Malm, Associate Professor Integrated Devices and Circuits, Kista Campus

Semiconductor Devices, Fall Gunnar Malm, Associate Professor Integrated Devices and Circuits, Kista Campus Semiconductor Devices, Fall 2014 Gunnar Malm, Associate Professor Integrated Devices and Circuits, Kista Campus gunta@kth.se, 08-790 4332 Semiconductor procesing at KTH Electrum Laboratory Stepper Lithography

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

Chapter 2. Electronics I - Semiconductors

Chapter 2. Electronics I - Semiconductors Chapter 2 Electronics I - Semiconductors Fall 2017 talarico@gonzaga.edu 1 Charged Particles The operation of all electronic devices is based on controlling the flow of charged particles There are two type

More information

Electronics EC /2/2012. * In-class exams: 40% 7 th week exam 25% 12 th week exam 15%

Electronics EC /2/2012. * In-class exams: 40% 7 th week exam 25% 12 th week exam 15% Arab Academy for Science, Technology and Maritime Transport Electronics EC 331 Dr. Mohamed Hassan Course Assessment * In-class exams: 40% 7 th week exam 25% 12 th week exam 15% *Tutorial exams and activities:

More information

Electron Energy, E E = 0. Free electron. 3s Band 2p Band Overlapping energy bands. 3p 3s 2p 2s. 2s Band. Electrons. 1s ATOM SOLID.

Electron Energy, E E = 0. Free electron. 3s Band 2p Band Overlapping energy bands. 3p 3s 2p 2s. 2s Band. Electrons. 1s ATOM SOLID. Electron Energy, E Free electron Vacuum level 3p 3s 2p 2s 2s Band 3s Band 2p Band Overlapping energy bands Electrons E = 0 1s ATOM 1s SOLID In a metal the various energy bands overlap to give a single

More information

Silicon Detectors in High Energy Physics

Silicon Detectors in High Energy Physics Thomas Bergauer (HEPHY Vienna) IPM Teheran 22 May 2011 Sunday: Schedule Silicon Detectors in Semiconductor Basics (45 ) Detector concepts: Pixels and Strips (45 ) Coffee Break Strip Detector Performance

More information

Semiconductors CHAPTER 3. Introduction The pn Junction with an Applied Voltage Intrinsic Semiconductors 136

Semiconductors CHAPTER 3. Introduction The pn Junction with an Applied Voltage Intrinsic Semiconductors 136 CHAPTER 3 Semiconductors Introduction 135 3.1 Intrinsic Semiconductors 136 3.2 Doped Semiconductors 139 3.3 Current Flow in Semiconductors 142 3.4 The pn Junction 148 3.5 The pn Junction with an Applied

More information

Carriers Concentration in Semiconductors - V. Prof.P. Ravindran, Department of Physics, Central University of Tamil Nadu, India

Carriers Concentration in Semiconductors - V. Prof.P. Ravindran, Department of Physics, Central University of Tamil Nadu, India Carriers Concentration in Semiconductors - V 1 Prof.P. Ravindran, Department of Physics, Central University of Tamil Nadu, India http://folk.uio.no/ravi/semi2013 Motion and Recombination of Electrons and

More information

Recitation 2: Equilibrium Electron and Hole Concentration from Doping

Recitation 2: Equilibrium Electron and Hole Concentration from Doping Recitation : Equilibrium Electron and Hole Concentration from Doping Here is a list of new things we learned yesterday: 1. Electrons and Holes. Generation and Recombination 3. Thermal Equilibrium 4. Law

More information

V = IR or R = V I. R = ρ l A

V = IR or R = V I. R = ρ l A Metals and Semiconductors Ram Seshadri MRL 2031, x6129, seshadri@mrl.ucsb.edu Electrical resistance and Ohm s Law: If an electric current I (units of A, Ampère) flows through a conductor with resistance

More information

Advantages / Disadvantages of semiconductor detectors

Advantages / Disadvantages of semiconductor detectors Advantages / Disadvantages of semiconductor detectors Semiconductor detectors have a high density (compared to gas detector) large energy loss in a short distance diffusion effect is smaller than in gas

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 Detectors are Ionization Chambers. Detection volume with electric field Energy deposited positive and negative charge pairs

Semiconductor Detectors are Ionization Chambers. Detection volume with electric field Energy deposited positive and negative charge pairs 1 V. Semiconductor Detectors V.1. Principles Semiconductor Detectors are Ionization Chambers Detection volume with electric field Energy deposited positive and negative charge pairs Charges move in field

More information