Geoffrey_Coram wrote on Sep 23rd, 2014, 2:29pm:Is your HFET model written in Verilog-A? There are a couple open-source models written in Verilog-A that include self-heating; it would be easy to copy their approach. (Mextram, Hicum, BSIMSOI, HiSIM-HV, ...)
Hi, Mr. Coram. I am recently using Verilog-A and Hspice to do electrical-thermal co-simulation, and interested in how they are implemented in other models.
As you suggested, I read the source code of Mextram and Hicum, focusing on their implementation of self-heating. There are two problems I do not quite understand.
1. The parameter system function,
$temperature, is used. According to "Verilog-AMS Language Reference Manual", it returns the circuit’s ambient temperature in Kelvin units.
My question is: where is that temperature assigned?
For an HSPICE simulation, the command ".TEMPERATURE" is used to specify the circuit temperature. Is this what I am looking for?
2. Is self-heating calculation only conducted once?
In most literature about the loosely-coupled algorithm between electrical and thermal fields, convergence is obtained by iteration between the two analysis.
In the “Mextram” model, I couldn’t find any iteration between electrical analysis and thermal analysis. So I wonder if the self-heating effect is taken into account and conducted only once in the model.
In the “Hicum” model, a
while() loop statement is used only to iterate for improved initial solution of total hole charge. Also, no iteration between electrical analysis and thermal analysis is found.
Could you give me some hint about how the self-heating is treated in these models?
Any help would be greatly appreciated.