A weird question about the simulatio result of ADS

[[email protected]]

Hello, everyone

I met a weird question when using ADS... We are simulating the I_D
current in the NMOS's saturation region that V_DS>=V_GS - V_TH>=0.

We also computed the current with the equation that
1/2*u_n*C_ox*W/L*[V_GS - V_TH]^2*(1+lamda*VDS). But the computed
results are 2X compared with the simulated results.

We get u_n, E_ox and T_ox directly from a 0.25 um parameter file for
ADS, and computed C_ox= E_ox/ T_ox. And the other setting for the
simulation is just the normal. So it is really werid to find that.
Could you help to give some suggestions?

Thanks a lot!

Jacobus
Jan. 18th, 2007

 

[Jim Thompson]

Hello, everyone

I met a weird question when using ADS... We are simulating the I_D
current in the NMOS's saturation region that V_DS>=V_GS - V_TH>=0.

We also computed the current with the equation that
1/2*u_n*C_ox*W/L*[V_GS - V_TH]^2*(1+lamda*VDS). But the computed
results are 2X compared with the simulated results.

We get u_n, E_ox and T_ox directly from a 0.25 um parameter file for
ADS, and computed C_ox= E_ox/ T_ox. And the other setting for the
simulation is just the normal. So it is really werid to find that.
Could you help to give some suggestions?

Thanks a lot!

Jacobus
Jan. 18th, 2007

You are using simplistic equations... while the simulator is using
complicated regional numeric solutions.

...Jim Thompson