I am using LTSpice with the following NMOS model from the library included in the famous book 'Sedra & Smith, Microelectronic circuits' :
* Level-1 Model for the 0.5-um NMOS Transistor (Part NMOS0P5)
* (created by Anas Hamoui & Olivier Trescases)
.model NMOS0P5 NMOS(Level=1 VTO=0.7 GAMMA=0.5 PHI=0.8
+ LD=0.08E-06 WD=0 UO=460 LAMBDA=0.1 TOX=9.5E-9 PB=0.9 CJ=0.57E-3
+ CJSW=120E-12 MJ=0.5 MJSW=0.4 CGDO=0.4E-9 JS=10E-9 CGBO=0.38E-9
+ CGSO=0.4E-9)
Well, to analyze my simulations, I try to make my pencil and paper analysis to notice possible differences.
However, I need to know several things about my MOS, and I can't find the factor ' K = mu_n * C_ox '.
Where should I find it ? Under which name ? I see that often other MOS models for SPICE include this factor in the model definition, which I can't find in the one I am using.
For information, this model, under SPICE, works perfectly well.
Thanks a lot for your help,
Ryl
Best Answer
It took some digging, but I found some definitions:
\$ \mu_n \$ is the electron mobility, which is \$ 1360 \frac{cm^2}{Vs} \$
\$ C_{ox} \$ is the capacitance per unit area of the oxide layer, which is \$ \dfrac {\epsilon_{ox}}{t_{ox}} \$
\$ {\epsilon_{ox}} = 3.45 \times 10^{-11} \frac{F}{m} \$
\$ t_{ox} \$ is the thickness of the oxide layer.
The only unknown appears to be the thickness of the oxide layer, which is already in your model (TOX = 9.5E-9), so you should be good to go.