Thermal conversion of GaAs

The conversion of semi-insulating GaAs to p type as a result of heat treatment in H2 was studied by photoluminescence (PL), secondary-ion mass spectrometry (SIMS), and transport measurements. The SIMS measurements resulted in the direct chemical identification of Mn near the heated surface. The correlation of the SIMS profiles with the results of PL and transport measurements indicated that Mn acceptors are responsible for the type conversion, and that substantial concentrations of Mn(?1017/cm3) are found in thin (1–3 μm) layers near the surface. The results of studies of samples heated under several different conditions showed that the Mn layers were not introduced by contamination from external sources during heat treatment, but were probably due to the presence of a bulk Mn concentration (