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 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.