Evaluation of plasma damage on InP sidewall induced by ICP-RIE

We investigated RF power and ICP power dependence of the reverse current of mesa type p-i-n diodes formed by inductively coupled plasma reactive ion etching (ICP-RIE) using CH₄/H₂/Cl₂. The reverse current increased extremely as the RF power increased. There was an optimum ICP power to minimize the reverse current. The reverse current increased at ICP power below and over the optimum power. AES depth profile measurements show that the carbon intruded to a deeper region from the mesa sidewall in samples etched at high RF power or low ICP power. The carbon intrusion was caused by ion bombardment damage. At higher ICP power, the ratio of indium to phosphorus was decreased due to the high reactivity of chlorine radical produced by ICP.