ABSTRACT
Device simulation is now an integral part of SiGe technology development, and is routinely used
for understanding SiGe HBT operation and device optimization. All the major commercial device
simulators support SiGe devices, including MEDICI from Avant (now Synopsys), DESSIS from ISE,
and ATLAS from Silvaco. They are typically part of a technology computer-aided-design (TCAD)
package, which includes process simulation, device simulation, and parameter extraction programs.
Fortunately or unfortunately, these device simulators were historically developed as general semicon-
ductor equation solvers, and the user must choose his or her model of physics, such as mobility,
carrier statistics (Fermi-Dirac or Boltzmann), bandgap narrowing (BGN), that best suit the device in
question. The default physical models are usually the simplest ones, and often give inaccurate results,
particularly for advanced device technologies such as SiGe. Users are also responsible for the ‘‘meshing’’
of the device structure, which can affect the simulation results significantly. This chapter addresses
these practical issues of device-level simulation for SiGe HBTs, and presents techniques of simulation
results analysis.
