Schred V2: Simulating n-type substrates and Vfb determination
Using the compiled Schred V2 code and supplied sample input files I am able to successfully model structures with a uniformly doped p-type Si substrate. I assume that to model an n-type substrate I need to change the sign of the parameter “Na”, which specifies the doping concentration. However, when I do this, I receive NaN values in the output “cv.dat” file for the capacitance in strong accumulation. The rest of the C-V curve looks alright. Am I doing something wrong here, or is this a bug in the code? Also, is there an easy way to determine the value of the flatband voltage from the simulation output? At the moment the best option I can see is to interpolate the values of fi_sc vs Vg to zero in the “av_dist.dat” file, but this is not precise.