characterization, modeling, and design of esd protection circuits

Appendix A
Tracer User’s Manual
Stephen G. Beebe, Zhiping Yu, Ronald J.G. Goossens, and Robert W. Dutton
In Technology CAD, the use of software to simulate the testing of semiconductor devices
is known as virtual instrumentation. A virtual instrument should be able to automatically
generate simulation data, e.g., I-V points along a bias sweep, given only the simple
specifications a user would input to a real programmable instrument testing a real IC
device. Numerical device simulators such as PISCES-2ET provide a means of creating
virtual devices and simulating electrical tests on the devices. However, these simulators
cannot trace through I-V curves with sharp turns unless the user carefully controls the bias
conditions near these turns--a tedious and time-consuming process. This deficiency
prompted the creation of Tracer.
Tracer is a C program which automatically guides PISCES and other semiconductor
device simulators through complex I-V traces and is ideally suited for device-failure
phenomena such as latchup, BVCEO , and electrostatic-discharge protection. Given a
PISCES input deck and a specification file with a PISCES-like syntax, a simulation can be
run over any current or voltage range without user intervention. Tracer is limited to dc,
one-dimensional traces, i.e., only one electrode can be swept per run. It sweeps this
electrode by dynamically setting the most stable bias condition at each solution point.
Additionally, Tracer has the ability to maintain zero-current bias conditions at one or two
electrodes during the trace, even at low device-current levels where such bias conditions
are unstable using traditional device simulation. The theory implemented in the Tracer
program was introduced in Chapter 3; a complete discussion is given in [28].
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