10 Feb 91 22:49
J. Robert Sims: Si mobility library v 1.1 for the HP48sx

I recently found a bug in my mobility library which caused it to crash
when given a negative temperature or doping density.  This mainly
caused a problem with the solver, which would often try negative
values when solving for the doping density.  The library now returns a
proper error, which the solver will ignore.

Here is a revised library to find the mobility of electrons and holes
in Silicon.  Both functions take the doping concentration (sum of
donor and acceptor concentrations) and the temperature as parameters.
If no units are specified, the function assumes the concentration is
in cm^-3 and the temperature is in Kelvins.  If one parameter has
units specified, both parameters must have units specified.  If units
are specified, the functions return a unit.  The number is in
cm^2/V*sec in either case.

The function and fit parameters for this program was taken from
Advanced Semiconductor Fundamentals, by Robert F. Pierret, Volume VI
in the Modular Series on Solid State Devices.  It is valid for a wide
range of temperatures and doping concentrations; T ranges from at
least 77 K to 475 K, and the doping from 0 to 10^19; it may be valid
for a wider range than this.

To use this program, strip off everything before the %%HP line.
Download it to your calculator, and convert to a library object using
ASC->.  Save this in a port by executing :n:1 STO (n STO also seems to
work for me; is this version specific?  All the docs say to use the
tagged method) where n is a port number (0 if you don't have a RAM
card).  Turn the calculator off and back on.  The library will
autoattach to your home directory.  Your stack and PICT will be
cleared.

[In the following, mu refers to the Greek letter Mu] 

The label muSi will be in your library menu; it contains the two
functions munSi and mupSi.  Put the total doping density in level 2
and the temperature in level 1, and execute the desired function.

This can be used in conjunction with the Equation Library card.  After
selecting the appropriate equations, simply put munSi(N,T) and
mupSi(N,T) into the variables mun and mup, respectively.  N should be
NA, ND, or NA + ND as appropriate.  For example, when using the NMOS
equations, put munSi(NA,T) in mun.  Run the multiple equation solver
as usual.

All disclaimers apply; if you have any problems please contact me via
email: jsims@vuse.vanderbilt.edu

