Electrical compensation in semi-insulating gallium arsenide

Abstract
Boat-grown gallium arsenide doped with both silicon and chromium has been subjected to Hall effect measurements, mass spectrometry, optical and electron microscopy, and localised vibrational mode (LVM) absorption measurements. The net silicon donor concentrations ((SiGa)-(SiAs)) determined by LVM exceeded the carrier concentrations measured electrically by (1.5*1017)-1018 cm-3 depending upon the silicon doping level. These discrepancies are attributed to acceptor levels associated with the chromium. A semi-insulating crystal has been prepared with a silicon concentration of 2*1017 cm-3.