Significant improvement in crystalline quality of molecular beam epitaxially grown GaAs on Si (100) by rapid thermal annealing

Abstract

Rapid thermal annealing (RTA) has been found to significantly improve the crystalline quality of epitaxial GaAs grown on Si (100) substrates. After RTA at 900 °C for 10 s, the percentage of displaced atoms near the GaAs/Si interface, as estimated by Rutherford backscattering/channeling, decreased from 20 to 7%. Photoluminescence intensity (PL) after RTA increased significantly (as much as sixfold in some cases), with the actual increase varying from sample to sample and with annealing conditions. In some cases, the PL intensity after RTA was comparable to the PL intensity obtained from GaAs grown on GaAs substrate under similar conditions. Rapid thermal annealing at 940 °C resulted in a degradation of the PL intensity as compared to annealing at 900 °C. Also, the PL peaks after RTA were found to shift to lower energies by 2–5 meV at low temperatures.