Interface study and preferred orientation of gallium oxide on silicon heterostructures

This study has highlighted the formation of an amorphous-nano-oxide film on Si substrate dominating the preferred orientation of sputtered β-Ga2O3. After the rapid thermal annealing (RTA) process from 700 to 1000 °C for β-Ga2O3 (100)/SiO2/p-Si, all the amorphous transformed into a β-Ga2O3 structure. Meanwhile, the thermal-induced massive twin boundaries and stacking faults generation have been observed in the annealing process above 800 °C. Therefore, an optimum metal-semiconductor-metal photodetector performance is achieved for the 800°C-RTA-treated β-Ga2O3 samples with the photo/dark current ratio of 3.91×102 and responsivity of 0.702 A/W (at 5 V bias). Furthermore, the interface energies per area (Ei) by density functional theory between β-Ga2O3 films ((001), (010), (100), and (-201)) with various facets and amorphous SiO2 were determine to quantify the sequence of the preferred orientations.