Analysis of electron transport properties in unstrained and strained Si1−xGex alloys

Abstract

A comprehensive and thorough investigation of electron transport properties in unstrained and strained Si1−xGex alloys is presented. Ohmic majority and minority drift mobilities, effective densities of states and saturation drift velocities are reported up to Ge contents of x = 0.3. The mobility model is verified by measurements of the in-plane majority drift mobility for various dopant concentrations and Ge contents. Saturation drift velocities are determined by full band Monte Carlo simulations. In strained Si1−xGex there is no substantial reduction of the mobility component perpendicular to the Si/SiGe interface above dopant concentrations of 10¹⁹ cm⁻³ for increasing Ge content x. In contrast, the saturation drift velocity decreases strongly for growing Ge content.