A selective low induced damage ICP dry etching process for a self-aligned InP-InGaAs HBT technology

We report on an inductively coupled plasma (ICP) process using CH/sub 4//H/sub 2//O/sub 2/ chemistry which have been studied for a self-aligned HBT technology. A very low bias voltage is used to reduce the induced damages. The study has concerned the ion flux characteristics: ion current and ion energy. Surface morphology, pattern profile, etch rates and induced damages were investigated as functions of ion energy and density for an optimized ICP reactor configuration. A comparison is made with an ICP process using a SiCl/sub 4/ chemistry. Finally, a selective process allowing one to attempt an almost full dry etching self-aligned process for HBT applications is described.