With increased interest in high-temperature, high-power, and high-frequency
devices based on SiC, the need for physical simulation models pertaining to
these materials becomes true. Device simulation is the commonly used term for a
continuous-field description in space and time, where the internal physical
quantities (e.g., the carrier concentration or the electrostatic potential
distribution) are considered as basic variables from which the static or
transient terminal currents and voltages are derived.
Device
simulation has gained increasing relevance for the design and optimization of
electronic semiconductor applications due to the rising design complexity and
the cost reduction achieved by reducing the number of experimental batch
cycles. Today, multi-dimensional general-purpose device simulators are
avaliable for modeling of different semiconductor materials from both academic
institutions and commercial vendors: DESSIS [18],
Taurus-Medici [19], ATLAS [20] and Minimos-NT [21]
are the most common to mention. These tools provide a coupled electrothermal
description of arbitrary device structures ranging from large high power
devices down to deep sub-micron VLSI structures including various physical
effects and external influences.
It is possible to apply the same
general concepts used for modeling of the conventional semiconductors to the
modeling of SiC electronic devices. Systematic work on modeling of SiC material
parameters for numerical simulation has been reported in 1994 by Ruff et
al. [22] on 6H-SiC, in 1997 by Bakowski et
al. [23] on 4H-SiC, and in 2000 by Lades [24] on both
4H- and 6H-SiC. However, as the quality of the SiC material improved in the
past few years, it is indispensable to employ an accurate quantitative
prediction of the SiC device performance based on the recent findings and the
relevant electrical properties for a specific device application. The
simulation work accomplished in this dissertation was carried out using the
general-purpose device simulator Minimos-NT [21].
Minimos-NT has been in an extensive development since it was first reported in
1994 by Fischer [25] and Simlinger [26]. The
simulator contains a comprehensive set of physical models that can be applied
to all relevant semiconductor devices and operation conditions. It solves
Poisson's equation, both carrier continuity and carrier energy balance
equation, the lattice heat flux equation coupled and decoupled. Furthermore, it
is capable to perform transient and AC-small signal analysis, and mixed-mode
simulations that incorporate physical devices and compact models in a circuit.
T. Ayalew: SiC Semiconductor Devices Technology, Modeling, and Simulation
