Modeling a device in SPICE

[aerial]

Hi

I am trying to model the IMOS transistor in SPICE, but I don't know where to start. I simulated the device in MEDICI and I have all the Current-Voltage characteristics, and the capacitances. The problem is that the Id-Vg and Id-Vds curves do not fit to MOSFET's equations. So I cannot modify a MOSFET model. I need to add equations to create the model. Could someone please help me on how to add equations to a model?
I use HSPICE, and if it does not offer such an option, is there any other tool?

Thanks.

 

[FvM]

With HSPICE, implementation of new analog device types can be done as proprietary model through the C++ programming interface, requiring profound knowledge of the SPICE analysator operation however. The same option exists with original Berkley SPICE. This method should be preferred, if a larger number of devices and/or long runs are intended in the analysis.

Another option is to design macromodels from analog behavioural blocks, implementing the device equations as far as needed for the present simulation task.

 

[aerial]

Thank you for the response. As I searched more, I found out that HSPICE can handle the lookup tables. Does the behavioral block include the lookup table option?