Electrical properties of lightly doped p-type silicon–germanium single crystals

Abstract

Experimental results are presented on the electrical properties of lightly boron doped bulk Si1−xGex as a function of the Ge content x in the range 0<x<0.13. Calculations of the hole mobility in Si and in Si1−xGex and comparison with experimental results allow us to estimate the averaged scattering potential of the randomly distributed Ge atoms to be 0.55 eV. From Hall effect and capacitance–voltage measurements, a Hall factor around 0.8 at T=300 K is derived. Hall effect measurements in the temperature range 20–300 K enable us to determine the boron acceptor activation energy, which decreases from 45 meV at x=0 down to 32 meV for x=0.13, and to estimate the hole effective masses to be meff/m0≈0.45.