
		      A SUBMICRON MOSFET

This is simulation of a 0.8 micron mosfet that reads a file containing the 
information to define the impurity doping profile as opposed to using the
pisces defined doping profiles.  The doping file supplies the concentration
versus depth information and is called depthcon.  A file such as depthcon
could be generated from a process simulator (such as SUPREM) and imported
into pisces in ascii format.

The device definition and the grid is generated using a file called ex13ig.p2.
The device is 3.08 x 3.00 microns.  The mesh is first generated and the
unnecessary points are eliminated.  The oxide and silicon regions are defined,
and electrodes are provided for the gate, drain, source and substrate.  The
doping, as mentioned earlier, is specified by depthcon.  The oxide of this 
device contains an interface charge of 3e10.  A outfile is generated that 
contains the doping information called DOP07.  The initial solution is 
obtained using the gummel method with the surface mobility reduced to 75%.
The device is then regrid to ensure more grid points around the junctions 
and an outfile is generated called M131.  The relevant doping profiles are
plotted to check that depthcon provided the desired information.

A curve for the drain current versus the gate voltage is simulated for by
a file called exn13g37.p2.  This file reads in the mesh file, the surface
mobility, the gate contact, the interface charge, and the models 
necessary for the simulation.  The initial solution is obtained using
a zero carrier gummel method.  A log file called G37LOG1 is started to 
store the simulation data.  A single carrier newton method is used to solve
for the gate characteristics.  The drain is biased at .05 volts and the 
gate voltage is varied from .3 volts to 8 volts.  Solution files are saved
at 4 and 8 volts called G37A and G37B.  Finally, the gate characteristics
are plotted.  

This example does not solve for the drain characteristics of the device, but
it can easily be done by biasing the gate at a particular voltage and then
slowly increasing the drain voltage, making sure that convergence is met.  
