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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.
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The George Washington UniversitySchool of Engineering and Applied ScienceDepartment 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.
Review of Spice Parameters Page 132 in Textbook .model nmos nmos Level=1 + Vto=1.0 Kp=3.0E-5 Gamma=0.35 + Phi=0.65 Lambda=0.02 Tox=0.1u + Nsub=1.0E+15 Nss=1.0E+10 Ld=0.01u + Tpg=1.00 Uo=700.0 Af=1.2 + Kf=1.0E-26 Is=1.0E-15 Js=1.0E-8 + Pb=0.75 Cj=2.0E-4 Mj=0.5 + Cjsw=1.00E-9 Mjsw=0.33 Fc=0.5 + Cgbo=2.0E-10 Cgdo=4.00E-11 Cgso=4.00E-11 + Rd=10.0 Rs=10.0 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 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
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.