Inductively coupled plasma etching of doped GaN films with Cl-2/Ar discharges

The inductively coupled plasma etching of undoped n- and p-type GaN films w as carried out with Cl-2/Ar discharges using different radio frequencies of 100 kHz and 13.56 MH2, in which the chuck power source operates. The etch rates with lower frequency of 100 kHz were greater than those with higher f requency of 13.56 MHz due to higher ion bombarding energy. The etch rates o f the GaN films with 100 kHz frequency increased substantially with increas ing pressure, while the etch rates with 13.56 MHz increased up to 20 mTorr and then decreased at higher pressures. The n-GaN showed somewhat faster et ch rates than undoped and p-type GaN films. The surface of the etched GaN f ilms showed quite smooth morphology, and the n-GaN showed some depletion of nitrogen from the etched surface. (C) 2000 The Electrochemical Society. S0 013-4651(00)01-033-8. All rights reserved.