How to add new parameters to a MOSFET SPICE model file?

Hi,

I need to add new additional parameters to the existing MOSFET model file in SPICE and thus obtain the VI characteristics and other plots for this new device? How can I achieve it?
Can someone please explain me the steps to do this? Also, please suggest the SPICE Tools which support this functionality?

Thanks in advance :idea:.
Raghu

You can obtain the VI characteristic without adding new parameters.

Anyway, which parameters would you like to add, and why? You can only use parameters which are understood within the model, and by the SPICE software tool you're using.

Hi Erikl,
I wish to model Ion Sensitive Field Effect Transistor (ISFET) in SPICE. I have Tanner Tool (T-SPICE). The equations related to ISFET have some additional parameters (Electrolyte parameters) in the standard MOSFET equations. So how can I go for it here?

Raghu.

erikl said:

You can obtain the VI characteristic without adding new parameters.

Anyway, which parameters would you like to add, and why? You can only use parameters which are understood within the model, and by the SPICE software tool you're using.

Click to expand...

I would recommend, then, that you try and dig up a
veriloga version of a standard FET model (like, try
Silvaco's web site) which will be somewhat human-
readable and let you edit equations as you see fit.
Then you need a version of SPICE, spectre, whatever
that supports veriloga code blocks.

Raghuram TR said:

I wish to model Ion Sensitive Field Effect Transistor (ISFET) in SPICE. I have Tanner Tool (T-SPICE). The equations related to ISFET have some additional parameters (Electrolyte parameters) in the standard MOSFET equations. So how can I go for it here?

Click to expand...

G00GLE for "isfet spice model". You'll find some papers , together with the usage of an also extended SPICE software tool called BIOSPICE, but prefers the usage of a macromodel - as suggested by dick_freebird - which can be used with a standard SPICE tool.

Hi Erikl and dick_freebird,

Thank you both .
Erikl, the paper (Modelling H+ - Sensitive FETs with SPICE) you gave is the one which I wish to implement in traditional SPICE. The model card parameters are given. But my doubt is where is the equation relating these parameters present in SPICE tool.
I could find the following model file form LTSPICE 4 and you can see the parameters listed.

* Copyright © 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Linear Technology Corporation. All rights reserved.
*
.model AO6407 VDMOS(pchan Rg=3 Rd=14m Rs=10m Vto=-.8 Kp=32 Cgdmax=.5n Cgdmin=.07n Cgs=.9n Cjo=.26n Is=26p Rb=17m mfg=Alpha_&_Omega Vds=-20 Ron=34m Qg=13n)
.model AO6408 VDMOS(Rg=3 Rd=4.8m Rs=3.6m Vto=1 Kp=90 Cgdmax=.7n Cgdmin=.25n Cgs=1n Cjo=.36n Is=36p Rb=6m mfg=Alpha_&_Omega Vds=20 Ron=12m Qg=18n)
.model AP9465GEM VDMOS(Rg=2 Vto=1.8 Rd=0 Rs=16m Rb=10m Kp=30 lambda=0.04 Cgs=600p Cgdmin=50p Cgdmax=800p Cjo=1.2n Is=3p mfg=Advanced_Power_Electronics Vds=40 Ron=25m Qg=8.5n)
.model BSB012N03LX3 VDMOS(Rg=0.5 Vto=2.77 Rd=612u Rs=183u Rb=383u Kp=1084 Lambda=0.09 Cgdmin=155p Cgdmax=2.32n A=0.6 Cgs=9.61n Cjo=8.84n M=0.3 Is=84p VJ=0.9 N=1.1 TT=3n mfg=Infineon Vds=30 Ron=1.2m Qg=62n)
.model BSB012N03MX3 VDMOS(Rg=0.5 Vto=2.52 Rd=572u Rs=183u Rb=373u Kp=1182.4 Lambda=0.07 Cgdmin=221p Cgdmax=3.09n A=0.6 Cgs=12.71n Cjo=8.84n M=0.3 Is=77.4p VJ=0.9 N=1.11 TT=3n mfg=Infineon Vds=30 Ron=1.2m Qg=82n)

and so on...

So how does the SPICE tool know the equation which uses these parameters? If that is found, I guess I can edit and create my own new equations with new extra parameters. Hope you got me.

dick_freebird , I am new to this Veriloga. So if my approach stated above is not working, I might have to switch to Veriloga.

Regards,
Raghu

erikl said:

G00GLE for "isfet spice model". You'll find some papers , together with the usage of an also extended SPICE software tool called BIOSPICE, but prefers the usage of a macromodel - as suggested by dick_freebird - which can be used with a standard SPICE tool.

Click to expand...

Raghuram TR said:

where is the equation relating these parameters present in SPICE tool.

So how does the SPICE tool know the equation which uses these parameters?

Click to expand...

Guess you didn't read my above answer thoroughly: With these ISFET model extensions, you can't use a standard SPICE tool, you need an extended SPICE software called BIOSPICE. Also, read this in the introduction of the S. Martinoia, G. Massobrio paper: "A behavioral macromodel of the ISFET in SPICE".

Hope you got me!