
		Example of Triggered Latchup
                ----------------------------

This is a latchup example of a cmos device in which the input to two
pulses is simulated, one that causes latchup (2ns), and the other that
recovers (1.75ns).  The cmos device used is a gaussian mock-up of the
old twin tubs structure.  A triangulation program called "tri" is used
to take the boundaries and grid them.  This griddig is fully geometric
based since no dopings have been specified.


What you will learn
-------------------
This example will teach you:
	1)  how to use tri to triangulage a region for simulation
	2)  the use of the smoothing parameter in the mesh and regrid
	     cards.
	3)  the effect of pulse width on latchup characteristics.

assumed Knowledge:
	This example assumes that you know about the use of UNIX shell
	scripts and have run the other examples to get a feel of the
	use of general PISCES commands.

Assumed Programs:
	This example assumes that PISCES has been installed such that the
	command

	pisc2

	will execute the program.

	The program tri, which is included in the utilities tape,
	must be installed such that the command

	tri

	executes the program.


A file called makegrid.p2 is used to generate the mesh.  The initial mesh
is generated using the "tri" program.  The doping is specified by the use
of analytic functions.  A regrid on doping is performed to generate the
mesh and is saved as mesh2a.   Appropriate dopings and junction are plotted.


Once we have the mesh, it's time to run the pulse simulations.
Two cases will be included - one that sustains latch-up and one
that does not. Note that EACH of these runs take about 3 CPU
hours on a CONVEX C1, a 6 MFlop machine.


The first case, a 2ns pulse, is performed in pulse2ns.p2.  The file
uses a two carrier newton method to solve for the transient latchup
condition.   With this pulse the latchup occurs.  If the make command
is used, the results will be plotted.


The second case, a 1.75ns pulse, is performed in pulse1.75.p2.
This case recovers.  This simulation is setup similar to the previous
simulation.


Please note that a Makefile is present for this example and as such the
simulation can be done by typing make in this directory.

