The extraction of simulation parameters performed in this chapter is based on long term statistical analysis. It relies on several different devices from different processes, as described in Chapter 5. In [50,51] a data extraction scheme was presented which is used and further developed: One consistent set of parameter values was found to describe various HEMT types based on the same technology. In this work simulation parameters are not extracted from one process or even measurements from one device and singularly fitted to high precision, but from a number of processes, that yield a mean value and ranges for deviations. Thus, several different technologies can be simulated.
As the most important transport parameter, the
mobility, is strictly correlated to typical measured carrier
sheet densities
. Data for
versus In content
in
the channel are compiled in Fig. 3.23. The data are
taken from GaAs based pseudomorphic AlGaAs/InGaAs HEMTs for
0.3, from metamorphic InAlAs/InGaAs HEMT for
0.53, and from lattice matched and pseudomorphic
InAlAs/InGaAs/InP HEMTs for higher
values. Double channel
HEMTs enter the figure by an average value [322].Changes of
the mobility data sheet densities
during MBE growth are
estimated from Hall mobility measurements, so that typical shifts are well known due to a high
throughput of MBE grown wafers.
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