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?
I hope if someone can give you a better answer for this question. However, I would like to give some comments or suggestions.
First of all you need to know that a particular SPICE tool which you are going to use does support those features or not. For example, if you want to use HSPICE and would like to manipulate the existing modelcard (PTM (Predictive Technonology Models)/PDK (Product Development Kit); you normally use command .PARAM, e.g. to change vth0 you can use .PARAM vth0=0.3424 (it can be any value other than the nominal value of ur PTM/PDK).
To use additional parameters: I can give you an example of Aging analysis where you have to give additional parameters in order to see the behaviour of your degraded device (e.g. nmos or pmos MOSFET etc.). For that, the following command is a basic example of using aging analysis and degraded additional parameter are e.g. tit0, titfd etc.
.model model_name mosra level=1 relmode=1
+tit0 = 5e-7 titfd = 7.5e-10 tittd = 1.45e-20
+tice=0 titlc=0 title=0 titwc=0 titwe=0
I hope if someone can give you a better answer for this question. However, I would like to give some comments or suggestions.
First of all you need to know that a particular SPICE tool which you are going to use does support those features or not. For example, if you want to use HSPICE and would like to manipulate the existing modelcard (PTM (Predictive Technonology Models)/PDK (Product Development Kit); you normally use command .PARAM, e.g. to change vth0 you can use .PARAM vth0=0.3424 (it can be any value other than the nominal value of ur PTM/PDK).
To use additional parameters: I can give you an example of Aging analysis where you have to give additional parameters in order to see the behaviour of your degraded device (e.g. nmos or pmos MOSFET etc.). For that, the following command is a basic example of using aging analysis and degraded additional parameter are e.g. tit0, titfd etc.
.model model_name mosra level=1 relmode=1
+tit0 = 5e-7 titfd = 7.5e-10 tittd = 1.45e-20
+tice=0 titlc=0 title=0 titwc=0 titwe=0
First, you need to pick a model for your MOSFET technology. Depending on what kind of technology you are referring to, you can select among very complex models to very simple ones. The parameters in the models are already provided by the mathematical equations (you can refer to the models depending on your SPUCE version/supplier). So, you can modify the value of these parameters and that is why is important you select the model according to what you want to modify........---> The problem comes when you want to add a "new parameter" to a model because that means you need to incorporate a "new model" to SPICE. To get around this problem most of SPICE engines allow you to input Verilog models, so you do not need to re-write and mess with the default models already in your SPICE version. However, the problem is not using Verilog, the problem is developing the model...........
Israel
Thanks for your input. I wish to model Ion Sensitive FET (ISFET) in SPICE. I have the equations which incorporate few additional parameters with regard to the electrolyte. Hence I need to add these parameters to the standard MOSFET equation and then plot the characteristics. The SPICE I am planning to use is T-SPICE (Tanner Tool). So how can I go for it here?
Well...I am not sure if new versions of T-SPICE allow you to input Verilog models. As far as version 13 you cannot. I would recommend more sophisticated tools such as SmartSPICE from SILVACO or HSPICE from SYNOPSIS. I would try to answer these questions first:
1.- What SPICE model are you going to use?
2.- Do you already have the model (equations) to describe the effect you are looking for in the electrolyte?
Israel
Hi,
1) For initial works, the SPICE model can be any. The prime focus is to modify the traditional MOS equations with additional parameters.
2) Yes, I do have the equations with new parameters. Please find the attached paper which specifies the same.
I could get the model file of standard MOS (from LTSpice) which has the conventional MOS parameters and their values. But my doubt is where are the equations present in SPICE which uses these parameters. Because only then the tool can plot the VI chara based on the equations. I guess my question is right!
Raghu
If you have the model already developed you can use Verilog to input these equations in SPICE. T-SPICE has that capability.
Israel
Ok. I shall explore that. But is there another option like I can provide the equations i SPICE and the corresponding new parameters in the model file and hence see the response? I could find the model file and parameters in it. But where does the equation involving these parameters present in SPICE? (How does the tool know the equation?)
Raghu
That is why you need to use Verilog. Verilog is a hardware description language used to input equations/models in SPICE. You can refer to a basic Verilog book to learn the language and T-SPCIE manual to learn how to input the equations. I can tell you I have done it before for Thin Film Transistors (TFTs) models.
Israel
Ok, I shall learn Verilog then. Even there is a OTFT counterpart for my model which I intend to do after this. I shall get back to you soon. Thank you so much Israel :).
Raghu
Hello, I am new to HSPICE, i have been trying for few days to add a discrete device model file into HSPICE. (As i have to first do DC operating point for verification of the plots with datasheet)
But for every model i download , the code is different. I don't know how to use it in the HSPICE (Either subckt, or libray or model ?) Its confusing
And i have looked through all the tutorial manuals and searched on internet forums. I have not found any particular example for adding the discete (vendor) model file to HSPICE.
It would be helpful, if anyone can tell me about . I want to add MOSFET "BSP130" model file to HSPICE.
http://www.nxp.com/products/discretes-and-logic/mosfets/standard-mosfets/n-channel-vertical-d-mos-logic-level-fet:BSP130?fpsp=1&tab=Design_Tools_Tab
I have same question about ISFET or other device which is about to sense the ion concentration in the electrolyte. How can I build the equivalent model about the behavior of pH change.
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