Fabrication of InGaAs/InP avalanche photodiodes by reactive ion etching using CH4/H2 gases

In this article, the first successful application of CH4/H2 reactive ion etching (RIE) techniques to the fabrication of an InGaAs/InP avalanche photodiode (APD) with very low dark current is reported. A partial charge sheet layer in the device periphery prepared by the CH4/H2 RIE was used for the fine control of electric field. On the top of the dry-etched partial charge sheet layer and charge plate layer, an n−-InP multiplication layer was grown by metalorganic chemical vapor deposition. Very low dark current less than 1 nA at 90% of breakdown voltage was obtained, indicating the minimal RIE-induced damages. The CH4/H2 RIE was shown to be applicable to devices operating under high electric field, such as APD’s.