High-Field Electron Transport in SiGe Alloy

Authors:
  • MEMaxim Ershov
    Maxim Ershov
  • VRVictor Ryzhii
    Victor Ryzhii

Abstract
Electron transport in unstrained Si1-xGex(0≤x≤0.4) alloy is studied in the present work using the Monte Carlo (MC) simulation technique. Electron transport characteristics (drift velocity, impact ionization (II) coefficient, etc.) are evaluated over a wide range of electric fields. It is found that not only low-field mobility but also saturation velocity and impact ionization coefficients are reduced with increasing Ge fraction due to alloy scattering. More importantly, the high-energy (ε>2 eV) electron population is reduced to a much greater extent than the ionization coefficient. Simple analytical expressions for electron low-field mobility, saturation velocity and II coefficient which can be easily implemented in device simulation programs are proposed.

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