Passivation of InSb photodetectors with atomic layer deposited Al2O3

The preparation of surface passivation layers on InSb is essential in the process of device fabrication. An Al₂O₃ passivation film was deposited on the surface of medium wave InSb film by atomic layer deposition (ALD). A series of variable area photodiode devices with different P/A ratios were fabricated. The performance of the device is characterized at 77K. The effects of ALD Al₂O₃ and anodic oxidation on the leakage current of diode devices were investigated. The surface leakage current of the passivated photodetectors was reduced by an order of magnitude over the anode sulfidation passivated photodetectors. Moreover, the metal-insulator-semiconductor (MIS) device were developed respectively, and the effects of different films as a dielectric layer on the interfacial characteristics were investigated.