Transcript PPT - SEAS - The George Washington University

The George Washington University
School of Engineering and Applied Science
Department of Electrical and Computer Engineering
ECE122 – Lab 7
MOSFET Parameters and Scaling Effects
Jason Woytowich
October 14, 2005
CMOS Scaling
• Devices are constantly shrinking in an
effort to increase the number of devices on
a chip.
• The state-of-the-art mass production is
moving into ~65nm.
• Clock speeds are scaled up to increase
performance.
Effects on the Device
• Short-channel effects on VT
• Velocity saturation
• Gate leakage current (IG)
• Subthreshold current (ID)
Effects on the Circuit
• Increased power consumption. Leads to
decreased supply voltage and smaller
noise margins.
• Increased role of wiring resistance,
inductance and capacitance.
• Interconnect coupling
• IR Drop
• Electromigration
Spice MODELS
• The standard spice model is not sufficient to
capture all of these effects.
• There have been many upgrades to it in order
to increase it’s effectiveness.
Level 1
~5 Parameters
Level 49
~100 Parameters
Review of Spice Parameters
Page 132 in Textbook
.model nmos nmos Level=1
+ Vto=1.0
Kp=3.0E-5
+ Phi=0.65
Lambda=0.02
+ Nsub=1.0E+15
Nss=1.0E+10
+ Tpg=1.00
Uo=700.0
+ Kf=1.0E-26
Is=1.0E-15
+ Pb=0.75
Cj=2.0E-4
+ Cjsw=1.00E-9
Mjsw=0.33
+ Cgbo=2.0E-10
Cgdo=4.00E-11
+ Rd=10.0
Rs=10.0
Gamma=0.35
Tox=0.1u
Ld=0.01u
Af=1.2
Js=1.0E-8
Mj=0.5
Fc=0.5
Cgso=4.00E-11
Rsh=30.0
Your task…
• Attempt to use a Level 1 Spice model to
model a “real” transistors IV characteristic.
• Measure the mean-square error.
• Error = 1/N SUM((IREAL-IMODEL)2)
• Bonus to the least error.
The “REAL” Data
• The IBM_018u.md file located under
homework 5 on the website will serve as
the real data.
The test setup
The simulation
• A DC sweep of 100 points of VDS from 0 to 1.8V
• A Secondary sweep of 10 points of VGS from 0
to 1.8V
.dc source VDS lin 100 0 1.8 sweep source VGS lin 10 0 1.8
.include "C:\Documents and Settings\Student\Desktop\ECE122_Lab7\ml1_typ.md"
*.include "C:\Documents and
Settings\Student\Desktop\ECE122_Lab7\IBM_018u.md"
.print dc i(M1,D)
* Main circuit: MosfetTest
M1 D G Gnd Gnd NMOS L=180n W=1u AD=66p PD=24u AS=66p PS=24u
VGS G Gnd 5.0
VDS D Gnd 5.0
* End of main circuit: MosfetTest
Example
What we want to see.
• The two graphs superimposed on each
other.
• The method/reasoning for your changes to
the model file.
• Any code you use to calculate the error.
• The model file.