Effect of buffer layer annealing temperature on the crystalline quality of In0.82Ga0.18As layers grown by two-step growth method

In0.82Ga0.18As epilayers were grown by LP-MOCVD on InP substrates with the insertion of In0.82Ga0.18As buffer layers, which were annealed at various temperatures between 490 °C and 630 °C for 5 min in AsH3 ambient. The effect of buffer layer annealing temperatures on the crystalline quality of In0.82Ga0.18As epilayers was investigated by atomic force microscopy, scanning electron microscopy, double-crystal X-ray diffraction, and room-temperature Hall measurement. The characterization results showed that high quality In0.82Ga0.18As epilayers were obtained by optimizing the annealing temperatures of buffer layers. In particular, the In0.82Ga0.18As epilayer with buffer layer annealed at 530 °C showed the best crystalline quality. The changes of crystalline quality of In0.82Ga0.18As epilayers at high and low annealing temperature can be attributed to the recrystallization and reevaporation of the In0.82Ga0.18As buffer layers.

► The buffer layer was thermal annealed at various temperatures to improve the crystalline quality of In0.82Ga0.18As materials grown by two-step growth method. ► The crystalline quality of In0.82Ga0.18As epilayers is very sensitive to the buffer layer annealing temperatures. ► In our experimental conditions, the In0.82Ga0.18As materials which have good quality and properties can be obtained when the buffer was thermal annealed at 530 °C.