NPN bipolar device model

[cmos_ajay]

Hello , I need a model file for NPN device, poly resistor and MIM capacitor for analog ic design. I am using LTSPICE and I need the model file for educational purpose only. Thanks.

 

[WimRFP]

Hello,

Do you mean the equations for the (Ebers-Moll / Gummel-Poon) model, or just a list of parameters for a particular transistor?

 

[cmos_ajay]

Hello, I need a list of npn BJT parameters for simulation in LTSPICE or HSPICE. I have a parameter model file for pmos and nmos devices and I am making a bandgap reference circuit. Thanks.

 

[erikl]

NPN bipolar device models can be very different. First, you must tell for which process (std. CMOS or BiCMOS) & which process size. Then: low-B parasitic lateral, or high-B BiCMOS npn ? Which SPICE level? Level 1 model (Gummel-Poon) ok?

 

[cmos_ajay]

Hello, I am using a 0.25um CMOS process (BSIM3) . The model file is level = 8. I am not sure of low-B parasitic lateral, or high-B BiCMOS npn. So either is fine with me.
Regards.

 

[erikl]

Hello, I am using a 0.25um CMOS process (BSIM3) . The model file is level = 8.

Level 8 BJT models are HiCUM models (s. the PDF below) and aren't easily available for CMOS processes. And all the 0.25µm std. CMOS processes I know don't support models for npn BJTs, sorry! Perhaps somebody could help you, if you show how you'd layout this npn.

Don't know if you can use the std. HiCUM model from below?
View attachment Level-8-BJT-HiCum_model.pdf

 

[salehk]

Hello,

Do anyone knows how the spice models(and equations) (either for cmos or bjt) are linked with parameters description file in cadence?
And do you know where is it located?
I need to know the exact calculations and maybe modify them for my own PDK. I am not using a specific PDK but need to design and model my own PDK suitable for my technology.

Thanks in advance.

 

[erikl]

... how the spice models(and equations) (either for cmos or bjt) are linked with parameters description file in cadence?

From Cadence' device parameters' descriptions, usually just the model and geometry values are used.

... do you know where is it located?

The models are in the simulator's model library. The geometry values are selected by the user.

I need to know the exact calculations and maybe modify them for my own PDK. I am not using a specific PDK but need to design and model my own PDK suitable for my technology.

You can find the exact calculations e.g. via the UC Berkeley's BSIM home page, but you probably won't be able to change them, as they are hard coded in the simulator. However, you can change any/all parameter(s) in the model files, or you may create your own models.

 

[salehk]

Thanks erikl,

Basically what I need is the calculations behind the model. So your Berkeley's BSIM link is very interesting, but I guess it focus on CMOS and doesn't include bipolar Gummel-Poon models.
Correct me if I am wrong. At least by looking at the documentation I cannot find it . any idea?

 

[erikl]

... it focus on CMOS and doesn't include bipolar Gummel-Poon models.
Correct me if I am wrong. At least by looking at the documentation I cannot find it . any idea?

You're right. The BJT models and equations can be found e.g. in this Avant's True-Hspice Device Models Reference Manual.

From level 6 (cf. p. 4-1) upwards, the Gummel-Poon model is covered quite well. The equations can be found at pp. 4-29 ff.