The PCIM analytical MOSFET model [3] used in the extraction is a continuous physically based MOSFET model for circuit simulation that takes into account bias dependent overlap capacitance and poly depletion effect observed in submicron MOSFETs. The PCIM model is incorporated as a built-in task module model. Thereafter, the extractions are performed using the nonlinear least squares optimization. Indeed the whole procedure of worst case corners determination, generation of I-V and C-V characteristics, and extraction of analytical model parameters can be automated using a script of task module commands.
The PCIM model accuracy in predicting the device characteristics for all bias and channel lengths of interest is excellent for both N- and P-channel devices. Typically the average fit error is within 3% for I-V and 10% for C-V data. Figures 6.3-6.6 show results for the N-channel typical case. Similar good agreement is also obtained for the remaining cases and for the P-channel data.
Figure 6.3:
Comparison of MINIMOS (symbols) and PCIM model (solid line) gate capacitance
calculated values for a device with length of 20
m and width
of 
m.
Figure 6.4:
Comparison of MINIMOS (symbol) and PCIM model (solid lines) overlap capacitance
capacitance values for a device with length of 
m for varying 
and width of 
.
Figure 6.5:
Linear region characteristics at zero for devices of width
of with length of 
, 
, and 
.
Figure 6.6:
ID-VD characteristics at varying 
and for devices with
length of 
, width of .