The effect of alloy scattering on the mobility of holes in a quantum well

Abstract

The effect of alloy scattering on the mobility of holes in a Si 1−x Ge x quantum well is considered from a theoretical perspective. Issues relating to the definition and value of the alloy potential are discussed, and results are presented showing how the alloy scattering component of the overall mobility varies with temperature, carrier density and alloy concentration. Screening is allowed for and found to be important at low temperatures. By considering other scattering mechanisms such as interface impurities, surface roughness and acoustic phonons, we argue that alloy scattering is not a significant limiting factor as regards device applications, contrary to recent claims.

Self-consistent energy balance simulations of hole dynamics in SiGe∕SiTHz quantum cascade structures

“…27 (set C), and the alloy scattering potential was set to 0.3 eV (normalized to the primitive cell volume). 32,47 The first example is a cascade of the simplest possible structure; i.e., a heterostructure stack of alternating wells and barriers. It has 16 monolayer ͑4.41 nm͒ Ge 0.3 Si 0.7 wells and 8 monolayer ͑2.15 nm͒ wide Si barriers, grown on a Ge 0.2 Si 0.8 virtual substrate.…”

“…Another important scattering mechanism in SiGe is the alloy disorder scattering, which is purely elastic, but nevertheless can induce hole transitions between different subbands. [30][31][32]20 Due to the nonparabolicity and anisotropy of the hole subbands, the scattering rates are evaluated numerically, using the linear tetrahedron method 17,33-36 of appropriate dimensionality.…”

Scattering analysis of 2DEG carrier extracted by QMSA in undoped Al0.25Ga0.75N/GaN heterostructures

“…The scattering of these electrons by conduction band disorder is called alloy disorder scattering. Kearley and Horrell [26] gave the mobility expression of alloy disorder scattering without screening effects as…”

Wave function-dependent mobility and suppression of interface roughness scattering in a strained SiGe p-channel field-effect structure

“…In the present work we have taken account of: ͑i͒ interface roughness scattering associated with random variations in the confining potential, 9 ͑ii͒ scattering due to strain fluctuations in the channel caused indirectly by the roughness, 10 ͑iii͒ scattering from interface impurity charges, 11 and ͑iv͒ alloy disorder scattering. 12 The standard model of interface roughness scattering gives…”