Characterization of deep levels in rapid-thermal-annealed AlGaInP

Effects of rapid thermal annealing (RTA) on deep-level defects have been studied for epitaxial layers of (Al0.25Ga0.75)0.52In0.48P, doped with Si and Be, grown on (100) GaAs substrates by the solid-source molecular beam epitaxy method. It appeared that RTA treatment affected significantly the net carrier concentrations at temperatures higher than 700 °C. Several deep levels were found. It was also found that RTA induced a new deep level with activation energy of about 0.5 eV in n-AlGaInP and another level with activation energy of 0.75±0.06 eV in p-AlGaInP. Annealing caused a change in trap parameters of the DX-center. Such a behaviour is believed to be due to a change in defect configuration or defect clustering. RTA also increased the concentration of another Si-related defect. An increase in net acceptor concentration observed for p-AlGaInP correlates with a decrease in concentration of a deep level with activation energy of 1.30±0.10 eV. This level is suggested to influence device performance characteristics.