Your cart is empty.
Keep shopping
Teach on Udemy
Turn what you know into an opportunity and reach millions around the world.
Learn MoreUndergraduate course on semiconductor device Physics-II
Rating: 4.8 out of 54.8(21 ratings)
428 students
Undergraduate course on semiconductor device Physics-II
Quantitative & Qualitative analysis of MOS capacitor, MOSFET and BJT
Created byExamekalavya Technical
Last updated 3/2022
English
What you'll learn
- MOS Capacitor quantitative analysis
- MOSFET quantitative and Qualitative treatment
- BJT analysis
- Mathematical understanding
Explore related topics
Course content
3 sections • 79 lectures • 9h 31m total length
- Lesson-01 MOS Introduction4:37
Explore the metal-oxide-semiconductor capacitor, a three-layer structure that behaves like a parallel-plate capacitor, with area-based capacitance given by permittivity over distance under applied voltage.
- Lesson-02 Energy band theory of MOS- Flat band condition5:25
Explore energy band diagrams across metals, insulators, and semiconductors and explain the flat band condition in MOS structures, including the Fermi level, band gaps, and equilibrium under no current.
- Lesson-03 Work function difference & Electron affinity7:05
Define work function as the energy difference between the vacuum level and the equilibrium Fermi energy for metals and semiconductors. Define electron affinity as the energy difference between the vacuum level and the conduction band, and discuss the intrinsic Fermi level at mid-gap and its relation to the energy gap.
- Lesson-04 Accumulation mode in energy bands9:50
Explore how negative bias on a metal contact drives hole accumulation at the semiconductor surface, bending energy band structure and forming a charge distribution at the metal insulator semiconductor interface.
- Lesson-05 Depletion mode in energy bands10:56
In depletion mode, the metal–semiconductor interface bends the semiconductor energy bands downward, repelling holes and depleting surface hole concentration via negative ions and a downward electric field.
- Lesson-06 Inversion mode in energy bands3:25
- Lesson-07 Inversion mode in energy band structure5:37
Describe inversion mode in the energy band structure at a semiconductor–metal junction, where band bending shifts the intrinsic energy level relative to the Fermi level and creates an inversion layer.
- Lesson-08 Surface potential5:53
Examine surface potential, its link to equilibrium and intrinsic Fermi levels, and the onset of strong inversion, while connecting electrostatic potential to electron and hole concentrations.
- Lesson-09 On set of strong inversion12:01
Describe the onset of strong inversion as the inversion-layer carrier concentration reaching the substrate's majority carrier concentration, with band bending and increased electron density in the inversion layer.
- Lesson-10 Surface potential-Summary9:56
Analyze how surface potential varies with band bending under flatband condition, accumulation, depletion, and inversion, defining key reference points and the onset of weak and strong inversion.
- Lesson-11 Maximum depletion width- Mathematical analysis11:27
Examine the maximum depletion width through a one-dimensional Poisson equation, linking surface potential to charge distribution and the onset of strong inversion in semiconductors.
- Lesson-12 Ideal MOS curves- Charge density6:49
Explore ideal MOS capacitor behavior, linking inversion and depletion regions to charge density via energy-band diagrams and oxide–semiconductor interface charges.
- Lesson-13 Ideal MOS curves- Field intensity & Potential6:34
Analyze ideal MOS curves by linking constant oxide-field and linearly varying semiconductor field to oxide and surface potentials, noting inversion-layer charge and the resulting linear-to-parabolic potential profile.
- Lesson-14 MOS C-V characteristic curve-I10:40
Explore the mos capacitor small-signal capacitance across accumulation, depletion, and inversion, highlighting oxide capacitance (cox) and depletion/junction capacitances (cj) that shape the c-v curve.
- Lesson-15 MOS C-V characteristic curve-II9:05
Explore the MOS C-V characteristic curve: how depletion width, inversion layer formation, and minimum capacitance vary with high- and low-frequency conditions, highlighting threshold voltage, W max, and oxide capacitance.
- Lesson-16 MOS capacitor with n-substrate4:03
This lesson examines the CV characteristics of a MOS capacitor with an n-substrate, highlighting accumulation, depletion, inversion regions, C_min, oxide capacitance, and frequency-dependent behavior at high and low frequencies.
- Lesson-17 Solved Example-014:29
Compute the maximum depletion width wmax in silicon by relating surface potential, acceptor and intrinsic concentrations, and permittivity, then evaluate with the given values to obtain wmax ≈ 1.4×10^-5 cm.
- Lesson-18 Solved Example-025:02
Compute the oxide capacitance for a 10 nm oxide layer, determine the maximum depletion layer charge, and derive the minimum capacitance of the C-V characteristic in semiconductor devices.
- Lesson-19 Threshold voltage & Inversion charge7:54
Investigate how threshold voltage arises from oxide capacitance and surface potential, and how the inversion layer charge and depletion region drive strong inversion in a semiconductor.
- Lesson-20 Non ideal conditions in MOS capacitor7:06
Explore non-ideal conditions in a MOS capacitor, including non-zero work function difference and oxide interface effects, and the resulting internal fields, Fermi level alignment, depletion, toward flat-band.
- Lesson-21 Non zero work function difference4:32
Examine how a non-zero work function difference arises under open circuit conditions. Consider modified work function and electron affinity and their influence on band bending at the oxide-semiconductor interface.
- Lesson-22 Oxide charges & Interface traps6:25
Examine how positive oxide charges and interface traps induce negative charges at the metal and semiconductor interfaces, shaping the internal electric field and threshold condition under open-circuit conditions.
- Lesson-23 Threshold voltage under non ideal conditions7:34
Explore threshold voltage under non-ideal conditions by balancing oxide charge and depletion charge, accounting for traps and oxide semiconductor interface effects, and analyzing the impact on strong inversion.
- Lesson-24 Solved example-033:11
Compute the metal-semiconductor work function difference under non-ideal conditions using modified work function and modified electron affinity with silicon doping data. Derive the barrier potential at the metal-semiconductor interface.
- Lesson-25 Solved example-042:59
Calculate oxide capacitance per unit area from the oxide permittivity and 500 nm thickness, then use 10 charges per unit area to obtain the work function related potential, about -1.13.
- Lesson-01 MOSFET- basic structure9:28
This lecture explains the basic structure and operation of the MOSFET, detailing its four terminals: source, drain, gate, and bulk, and the enhancement and depletion modes controlled by the gate.
- Lesson-02 Induced channel & Implanted channel4:16
Explore induced and implanted channels in mosfets, contrast enhancement and depletion modes, and explain inversion layers, mos capacitor behavior, and the role of gate and threshold voltages in the channel.
- Lesson-03 Threshold voltage for a MOSFET6:38
Explore how depletion and enhancement MOSFETs differ in drain current and channel formation, and define threshold voltage as the minimum gate bias to establish or disable conduction.
- Lesson-04 MOSFET 3-D structure2:50
Explore the three-dimensional mosfet structure on a silicon substrate, contrasted with its two-dimensional representation, and highlight channel length, oxide thickness, and gate material options like metal, aluminium, or polysilicon.
- Lesson-05 MOSFET operation in linear region9:52
Explain MOSFET operation in the linear region, showing how gate voltage forms an inversion layer to enable drain current and how current relates to threshold and channel conductance.
- Lesson-06 MOSFET operation in saturation region13:16
Explore MOSFET operation in saturation, including the transition from linear behavior, inversion layer formation, channel length modulation, and current that remains constant beyond saturation.
- Lesson-07 n-MOSFET characteristics10:32
this lecture analyzes the n-mosfet transfer and output characteristics in enhancement and depletion modes, defining threshold, saturation current, and the respective saturation points.
- Lesson-08 p-MOSFET characteristics7:40
Explain p-mosfet characteristics in enhancement and depletion modes, including negative threshold voltages and the onset of drain current, with three-terminal representations, saturation and linear regions.
- Lesson-09 MOSFET current equation-I(derivation)11:35
Derive the MOSFET current equation in saturation and linear regions, linking drain current to W/L, mobility, oxide capacitance, and gate voltage through inversion layer concepts.
- Lesson-10 MOSFET current equation-II(derivation)4:49
Derives the mosfet saturation current equation, showing ids(sat) = (w/l) mu_n c_ox (v_gs - v_t)^2 / 2.
- Lesson-11 Output conductance & Transconductance5:21
Define and analyze transconductance and output conductance in MOSFETs, deriving gm as dId/dVgs at constant Vds and gds as dId/dVds at constant Vgs across linear and saturation regions.
- Lesson-12 Channel length modulation10:17
Examine channel length modulation in MOSFET saturation, where the drain current deviates from ideal behavior as the effective channel length shortens (L' = L - delta L) with lambda.
- Lesson-13 Threshold voltage6:50
Learn how to control threshold voltage in enhancement-mode MOSFETs for switching, considering substrate doping and oxide capacitance, and shift the threshold via implant, body effect, oxide thickness, or polysilicon gates.
- Lesson-14 Threshold tailoring implant8:16
Explore threshold tailoring via shallow boron implantation beneath the oxide to form a negative charge sheet that shifts the MOSFET threshold voltage toward a positive value.
- Lesson-15 Body bias effect5:40
Understand the body bias effect, or substrate bias, and how bulk potential VB modifies the depletion region between source and bulk, shifting the threshold voltage.
- Lesson-16 Oxide layer thickness5:33
Explain how oxide layer thickness affects oxide capacitance per unit area and raises the threshold voltage. Show how thick insulation isolates a parasitic transistor on a chip in VLSI MOSFETs.
- Lesson-01 BJT Introduction11:11
This lecture introduces the bipolar junction transistor, its three-terminal two-junction structure with emitter, base, and collector, and explains the emitter-base and base-collector junctions, current directions, and common configurations.
- Lesson-02 BJT Basic operation7:06
Explore the basic operation of a bipolar junction transistor, including forward bias of the emitter-base junction, minority-carrier injection, and their sweep into the collector under reverse saturation.
- Lesson-03 BJT Operation(Contd....)9:07
Explore how forward bias injects holes from the emitter into the base, generating collector current, while doping and base width control recombination and diffusion length for efficient collection.
- Lesson-04 BJT Operating regions4:10
Explore BJT operating regions, including forward active, saturation, cutoff, and reverse active, and learn how transistors amplify signals and switch between on and off states.
- Lesson-05 BJT Under thermal equilibrium12:40
Examine a bipolar junction transistor in thermal equilibrium under open-circuit conditions, focusing on emitter-base and base-collector junctions, depletion regions, charge distribution, and field and potential profiles.
- Lesson-06 BJT in forward active region6:47
Examine how forward bias in a BJT alters emitter-base and base-collector fields, densities, and energy levels to enable forward-active operation.
- Lesson-07 BJT current components9:22
- Lesson-08 BJT Common base current gain6:30
Explore the common-base current gain in a BJT, defined by the transport factor alpha. Relate collector current to emitter and base currents via alpha and gamma.
- Lesson-09 solved example-013:37
compute transport factor and emitter efficiency from the given current components, then use alpha and gamma to obtain the common-base parameter as their product and estimate related currents.
- Lesson-10 Minority carrier distribution in BJT7:23
Explore minority carrier distribution in a BJT under forward bias, deriving injected carrier profiles in emitter, base, and collector, and applying exponential variation with a linear base approximation.
- Lesson-11 Minority carrier concentration-Mathematical analysis6:28
Apply the continuity equation to derive the minority carrier concentration for holes as a function of x, using diffusion, diffusion coefficient, and boundary conditions.
- Lesson-12 BJT current equations-I6:51
Derive BJT current equations from minority carrier distribution, defining emitter and collector currents as diffusion currents in the base, using boundary conditions and diffusion coefficients DP and WB.
- Lesson-13 BJT current equations-II3:58
Derive BJT currents by analyzing minority-carrier diffusion in emitter and collector regions, incorporating reverse saturation current and forward-emitter-base bias with the exponential term exp(V_EB/V_T) - 1 to obtain current expressions.
- Lesson-14 BJT emitter current- Mathematical expression5:07
Derive the BJT emitter current expression from minority carrier distributions, showing how emitter current depends on minority carrier concentrations and constants, and discuss its exponential relation.
- Lesson-15 BJT collector and Base currents-Mathematical analysis6:02
Analyze BJT collector and base currents through minority-carrier expressions in forward-active operation. Derive emitter, collector, and base currents from minority-carrier distributions and relate them via defined constants.
- Lesson-16 Emitter efficiency revisited6:55
Revisit emitter efficiency gamma by defining it as the ratio of emitter injection current to total emitter current, and show how base and emitter doping affect gamma.
- Lesson-17 Solved example-025:26
Compute the emitter efficiency and gamma for a p+-n transistor using given emitter and base dopings, lifetimes, diffusion lengths, and emitter width, yielding gamma ≈ 0.9991.
- Lesson-18 Minority carrier distribution-I8:20
Explore minority carrier distribution in forward-active transistor operation, deriving current components from injected carriers and their exponential variations across emitter, base, and collector under forward and saturation conditions.
- Lesson-19 Minority carrier distribution-II3:45
Explore how minority carrier concentrations vary exponentially near a p-n junction under forward and reverse bias, with carrier injection, diffusion in the neutral base, and saturation effects.
- Lesson-20 Generalized current expressions4:28
Derive generalized emitter and collector current expressions that apply to all transistor operating regions, including forward active, saturation, and inverse active, with currents tending to zero in saturation.
- Lesson-21 Ebers-moll model7:55
this lecture presents the Ebers-Moll model of a bipolar transistor as two back-to-back diodes, linking emitter and collector currents via alpha factors and junction interaction.
- Lesson-22 Base width modulation or early effect7:08
Explore base width modulation and the early effect in a bipolar junction transistor, showing how increasing bias narrows the base, reduces recombination, and raises collector current.
- Lesson-23 Transistor configurations7:02
Explore transistor configurations, including common base, common emitter, and common collector. Analyze their input and output characteristics, voltages, and currents, with independent and dependent variables.
- Lesson-24 Common base configuration-Input characteristics7:25
In the common-base configuration, the lecture links input voltage and current (V_BC and I) and shows how increasing V_BC shifts the input characteristic left, increasing emitter current.
- Lesson-25 Common base configuration output characteristics8:12
Explore how the common-base transistor's output characteristics show collector current following emitter current through forward bias, with injected minority carriers, across active, saturation, and cutoff regions.
- Lesson-26 Common emitter configuration9:08
Analyze the common emitter configuration, including input and output currents and biasing, and explain how alpha and beta govern collector current and gain.
- Lesson-27 CE configuration-Input characteristics6:03
Explore how the input characteristics of a common emitter transistor shift with collector voltage due to the Early effect, illustrating input curves, forward bias, and base-emitter behavior.
- Lesson-28 CE configuration-Output characteristics7:14
Examine the output characteristics of a common-emitter transistor, showing how collector current varies with base current, saturation and active regions, and the role of base width modulation and early effect.
- Lesson-29 BJT as an amplifier8:49
Explore how a bipolar junction transistor operates as a common-emitter amplifier, using load lines and the Q point to enable small-signal gain, while highlighting frequency-dependent beta and the cut-off frequency.
- Lesson-30 Unity gain frequency and transit time7:08
Relate unity gain frequency to transit time in the neutral base region by deriving the cutoff frequency from base width and diffusion coefficients, highlighting current gain behavior.
- Lesson-31 BJT as a switch8:30
Examine the switching action of a bjt in a switch configuration, showing how a rectangular input signal drives transitions between on and off states via base current changes.
- Lesson-32 BJT switching action complete analysis10:32
Analyze BJT switching action by detailing how minority-carrier injection and base-charge variation drive transitions between active and saturation regions, shaping the collector current and carrier lifetimes.
- Lesson-33 Early voltage2:49
Examine the early voltage by extrapolating the linear region of the output characteristics to their intercept, and define the output conductance from the ratio of ΔI_C to ΔV_early.
- Lesson-34 Breakdown mechanisms- punch through9:48
Explain how breakdown in a bipolar junction transistor occurs via punch through and avalanche multiplication, linking punch through to the early effect and related expressions.
- Lesson-35 Breakdown mechanism- Avalanche multiplication15:54
Explore the avalanche multiplication and breakdown mechanisms in bipolar transistors, including base-open and emitter-open configurations, and derive the current gain m = 1/(1−α) under breakdown conditions.
- Lesson-36 Solved example-039:18
This solved example analyzes reverse-biased transistor operation, showing how emitter and base doping affect depletion region and base width through built-in potential calculations and related formulas.
- Lesson-37 Solved example-044:06
Solve a semiconductor device physics problem to determine the punch-through base width in a BJT using depletion-region relations, emitter and collector doping, and a 0.5 μm base width.
- Lesson-384:13
Analyze how a bipolar transistor's neutral base governs injected minority-carrier electrons and diffusion. Use maximum electron concentration and diffusion coefficient to estimate diffusion current density, noting linear approximation is invalid.
Requirements
- My previous course- "Undergraduate course on semiconductor device physics-II"
Description
This is an undergraduate course on semiconductor device physics. This course is the second part in a series of two courses on semiconductor device physics.
For any electronics student understanding transport phenomena of charge carriers, drift current, diffusion current, energy band theory of semiconductors, electron hole pairs(EHPs), Junction formation in a diode, extending the device physics to three terminal devices like BJT and MOSFET is necessary.
My previous course "undergraduate course on semiconductor device physics-I" is a prerequisite for complete understanding of this course.
Metal-Oxide-Semiconductor combination forms a capacitor and that capacitive action is to be understood well in terms of threshold voltage, CV characteristics. Though our major focus is on ideal MOS capacitor, non-idealities are also discussed up to some extent.
Based on the knowledge of MOS capacitor, if we look at the transport of charge carriers in a three terminal device MOSFET it gives a complete picture of all MOSFET transistor structures namely, enhancement MOSFET & depletion MOSFET in both p-type and n-type substrates. A MOSFET is explained up to threshold control.
Another transistor is Bipolar junction transistor(BJT). BJT characteristics and device parameters are explained with respect to input and output characteristics.
About Author:
Mr. Udaya Bhaskar is an undergraduate university level faculty and GATE teaching faculty with more than 15 years of teaching experience. His areas of interest are semiconductors, electronic devices, signal processing, digital design and other fundamental subjects of electronics. He trained thousands of students for GATE and ESE examinations.
Who this course is for:
- Undergraduate students in electronics engineering, Communication engineering