ENGR338 Lab 2021 Spring
Lab 4 MOSFETs and IV Curves
Name: Keon Nez
Email: ktnez@fortlewis.edu
MOSFETs and IV Curves
Introduction
MOSFET
stands for Metal Oxide Silicon Field Effect Transistor or Metal Oxide
Semiconductor Field Effect Transistor.The construction of a MOSFET is a
bit similar to the FET. An oxide layer is deposited on the substrate to
which the gate terminal is connected. This oxide layer acts as an
insulator (sio2
insulates from the substrate), and hence the MOSFET has another name as
IGFET. In the construction of MOSFET, a lightly doped substrate, is
diffused with a heavily doped region. Depending upon the substrate
used, they are called as P-type and N-type MOSFETs.
Materials
- Operationg Systems: Electric VLSI and LTSpice
- Libraries of the ideal ADC/DAC - Found here
- Reference simulations and configurations from Dr. R. Jacob Baker, of UNLV
Methods
- Design a MOSFETs in Electric.
- Understand the operation/simulations to analyse the IV curves of the MOSFETs.
Results
The N-channel MOSFETs are simply called as NMOS. The symbols for N-channel MOSFET are as given below.
The P-channel MOSFETs are simply called as PMOS. The symbols for P-channel MOSFET are as given below.
Going
through the lab tutorial's constructional details of an N-channel
MOSFET. Usually an N-Channel MOSFET is considered for explanation as
this one is mostly used. Also, there is no need to mention that the
study of one type explains the other too.
Verifying
the above schematic (NMOS) matches the layout (performing an NCC).
Finally simulating the schematic. The end result of the N-channel
MOSFET is seen below.
Again
verifying
the above schematic (PMOS) matches the layout (performing an NCC).
Finally simulating the schematic. The end result of the P-channel
MOSFET is seen below.
Discussion
Particularly
for MOSFETs it should be noted that in the small V DS region -- before
the saturation region -- the MOSFET characteristic curves look like
nearly straight lines through the origin. V G controls the slope of
these lines, so the MOSFET acts like a variable resistor with a voltage
( V G ) control.