Silicon doping from disilane in gas source MBE of GaAs

Abstract

Disilane (Si 2H 6) is used as an n-type dopant in gas source molecular beam epitaxial growth of GaAs using triethylgallium (TEG) and AsH 3. A linear relationship is obtained between the disilane flow rate and the electron concentration in the range from 1.3×10 17 to 1.2×10 18 cm -3. The doping efficiency depends on the substrate temperature varied from 480 to 600°C, but only slightly on the AsH 3 flow rate. Furthermore, the doping efficiency is observed to be enhanced by a factor of 2.5 when UV laser irradiation is directed normal to the substrate surface.