Dry etching of InGaN/GaN multiple quantum-well LED structures in inductively coupled Cl₂/Ar plasmas

A parametric study of the etch characteristics of InGaN/GaN multiple quantum-well (MQW) light-emitting diode (LED) structures has been carried out with Cl₂/Ar in an inductively coupled plasma (ICP) discharge. The etch rate increased with Cl₂ concentration up to 60% and remained relatively constant at higher Cl₂ percentages. It also increased monotonically with the ICP source and the rf chuck powers. The attainable etch rate for the InGaN/GaN MQW structures was about 4,500 Å/min under moderate ICP conditions: 700 W ICP source power, 100 W chuck power, 10 mTorr, and 50% Cl₂. The experimental results overall showed that the dominant etch mechanism of the ICP etching of the InGaN/GaN MQW LED structures was an energetic ion-enhanced chemical etching.