PISCES-2ET and Its Application Subsystems - Stanford Technology ...

CHAPTER 4
Material Properties for
Heterostructures
In CHAPTER 2 and APPENDIX A, expressions are introduced for carrier transport in
heterostructures. In order to perform the simulation, essential material parameters must be known. In
this chapter, we will mainly discuss various material properties needed for device simulation and their
dependence on the composition.
4.1 Material Parameters for Device Simulation
Material parameters in compound semiconductors depend strongly on the composition as well as (to a
lesser degree) on the doping level. We start with identifying which material properties (parameters)
are mostly concerned in the device simulation and then discuss the composition dependence in terms
of mole fraction. Beside, the lattice temperature effect on some parameters will also be mentioned.
The minimum set of material parameters which have to be known in order to proceed the
device simulation include:
1. Electron affinity, χ , and conduction band edge offset due to the composition change.
2. Energy bandgap, E g .
* *
3. Effective masses for electrons and holes, m n and m p , from which the effective densities of states
for the conduction and valence bands, N C and N V , can be derived (Eq. (2.4)).
4. Static and high-frequency dielectric constants, and .
ε 0
ε ∞
PISCES-2ET – 2D Device Simulation for Si and Heterostructures 33