Improved thermal stability of In/sub 0.53/Ga/sub 0.47/As metal-semiconductor-metal photodetectors with Al2O3 interfacial layer

The thermal stability of In/sub 0.53/Ga/sub 0.47/As metal-semiconductor-metal photodetectors has been improved by using thin electron-beam evaporated Al
₂
O
₃
interfacial layers of different thickness. The addition of the interfacial layer allows for an increase in anneal temperature from 250/spl deg/ to 350/spl deg/C with a four-fold dark current increase. Measurements of impulse responses at 1.3 μm showed, that the frequency behaviour is not adversely affected by the increased capacitance caused by oxide charges, since metal-semiconductor-metal photodetectors are carrier transit-time limited.