EEE436
Ideal DC Current Voltage Relationship
for JFETs
L1303
Derivation of the I-V Characteristics
Consider an n-channel JFET with the geometry shown,
representing half of a two-sided symmetrical geometry. The
channel resistance varies with along the cha
EEE436
The MESFET
L1304
The MESFET
The MESFET is the same basic device as the JFET,
except that the pn junction is replaced by a Schottky
barrier rectifying junction.
Since the electron mobility in GaAs is much larger than
the hole mobility, we will con
EEE436
Non Ideal Effects
L1305
Channel Length Modulation
In deriving the current equations, we have implicitly
assumed that the channel length was constant.
The neutral n-channel length decreases as
increases; thus the drain current will increase.
The
EEE436
The Device Characteristics
L1302
The Device Characteristics
The figure shows a symmetrical, two-sided pn JFET
and a MESFET with the semi-insulating substrate.
We derive the ideal DC current-voltage relationship
for both devices by simply consider
EEE436
Optical Absorption
L1401
Optical Absorption
Due to wave-particle duality, light waves can be
treated as particles, which are referred to as photons.
The photon energy is = where is Planks
constant 6.626 1034 and is the
frequency.
The relationshi
EEE436
Solar Cells: Technologies
L1403
Commercial Si Solar Cells
Best single
crystal cell
efficiencies are
now >25%, and
module
efficiencies are
over 20%.
Poly or Mulitcrystalline Si is
cheaper to
produce than
single crystal Si,
but material
quality is
EEE436
Solar Cells: Basic Operation
L1402
The pn Junction Solar Cell
An incident photon with > creates an electron-hole
pairs; if it is in or near the SCR, the electron and hole are
swept across, producing a photocurrent .
The photocurrent produces a vo
EEE436
Equivalent Circuit and Frequency
Limitations
L1306
Small-Signal Equivalent Circuit
A cross section of an n-channel JFET is shown, with parasitic
source and drain series resistances. The substrate may be
semi-insulating gallium arsenide or a + type
EEE436
High Electron Mobility Transistor
L1307
Modulation Doping
As discussed earlier (Chap. 9), an isotope heterojunction
between, for example, GaAs and the wider bandgap
AlGaAs, forms a 2-dimensional electron gas (2DEG) at
the interface between the two
EEE436
The Junction Field-Effect Transistor
L1301
Basic pn JFET Operation
The junction field-effect transistor ( JFET)
consists of an n region (the channel) between the two
p regions, and majority carrier electrons flow between
the source and drain termi
EEE436
Review of Density of States and
Semiconductor Statistics
R0104
Density of States
Eventually the crystal size imposes a finite number of values on the possible k-values an
electron may assume. We are interested in:
# +
=
If we consider that th
EEE436
Overview of Semiconductor Devices
R0101
60 Years of Progress
John Bardeen
Walter Brattain
William Shockley
Bell Laboratory - 1947
1 Transistor:
Germanium point contact BJT
Intel 62-Core Xeon Phi
5,000,000,000 transistors,
2012
Motorola PC 620 - 199
EEE436/591 Fundamentals of Solid State Devices, Spring 2017
Homework Assignment 1 Solutions, 100 pts
Problems 7.39, 8.39, 9.7, 9.13
Problem 7.39 (25) An abrupt silicon p+n junction has an n-region doping concentration
of Nd=51015 cm-3. What must be the mi
EEE436/591 Fundamentals of Solid State Devices, Spring 17
Homework Assignment 1 Solutions, 75 pts
Problems 1.11, 3.12, 4.45
Problem 1.11 (25). The crystal structure of sodium chloride (NaCl) is a simple cubic
with the Na and Cl atoms alternating positions
EEE436/591 Fundamentals of Solid State Devices, Spring 2017
Homework Assignment 5 Solutions, 100 pts
Problems 10.2, 10.7, 10.10, 10.30
Problem 10.2 (a) Calculate the maximum space charge width, and the maximum space
charge density () in a MOS capacitor wi
EEE436/591 Fundamentals of Solid State Devices, Spring 2017
Homework Assignment 4 Solutions, 100 pts
Problems 9.18, 9.23, 9.27, 9.32
Problem 9.18 A Schottky diode at T=300 K is formed between tungsten and n-type silicon
doped at Nd=1016 cm-3. The cross-se
EEE436/591 Fundamentals of Solid State Devices, Spring 2017
Homework Assignment 2 Solutions, 100 pts
Problems 5.16, 7.22, 7.28, 8.24
Problem 5.16 (25). An n-type silicon material at T=300 K has a conductivity of 0.25 (-cm)-1.
(a) What is the donor impurit
EEE436
Review of Energy Bands
R0103
Covalent Bonds
The hydrogen molecule (2+ ) is the model for
covalent bond.
When two isolated atoms are brought together,
the 1s orbitals of atomic hybridize to form a lower
energy bonding orbital and a higher energy a
EEE436
Review of Intrinsic and Extrinsic Carrier
Concentrations and Band Diagrams
R0105
Intrinsic Concentration
The equilibrium electron and hole concentrations assuming non-degenerate
statistics are given by
,
2,
=2
2
3/2
=
= 1 ( )/
For a semicon
EEE436
Review of Semiconductor Crystal
Structure
R0102
Structure of Materials
Materials can be roughly classified according to their long range order and dimensionality:
Crystalline-Long range order characterized by a periodic crystal lattice
Polycrysta
EEE598 Midterm
Take-home, open book/notes/internet
Assigned on 3/2/2017
Due 3/14/2017 midnight on blackboard
5 problems, 100 points
Name:
ID#:
Lecture notes and references on blackboard
Electric Vehicle Machines and Drives: Design, Analysis and Applicatio