The chemical inertness and high bond strength of GaN material do not permit a simple wet etch process for pattern transfer in fabrication of devices. It has been demonstrated inductively coupled plasma could significantly improve etching process producing a highly anisotropic etch profiles and high etch rate. Etching of InGaN/GaN multiple quantum wells (MQWs) materials was performed using inductively coupled Cl2/Ar plasmas, and the effects of main process parameters such as gas flow rate, induction rf power, self bias voltage, chamber pressure on the etching mechanisms and their relations to the etch rates and morphologies of InGaN/GaN materials was investigated. InGaN/GaN etch rates increased with the increase of chlorine radical density and ion energy, and a vertical etch profile having an etch rate over 450 nm/min could be obtained at 350 W induction power and -400 V bias voltage. The etch rate of InGaN/GaN MQWs appeared to be more affected by the chemical reaction between Cl radicals and GaN compared to the physical sputtering itself.
中正嶺學報=Journal of Chung Cheng Institute of Technology 34(2)，頁185-190