Hspice problem about warning

[yadiw]

"Warning: Acde = 1 may be too small in BSIM4 model pmos with w=2.4e-007 l=3.2e-008.

Warning: (B1 + Weff) may be too small in BSIM4 model nmos with w=9.6e-008 l=3.2e-008.

Warning: Acde = 1 may be too small in BSIM4 model nmos with w=9.6e-008 l=3.2e-008."

im getting this warning in .lis file when simulating...
can any one say what this mean and how to solve it...

 

[erikl]

Acde is a factor in the exponential coefficient used for the calculation of X_DC, the DC charge thickness in accumulation and depletion regions, and is used in the Charge-Thickness Capacitance Model mainly to calculate the C_GB capacitance correctly - cf. the BSIM documents.

You may either ignore these warnings, or try with a slightly larger Acde value, up to Acde=1.6 .