The effect of EB irradiation with and without hot-jet Cl2 on an ultra-thin GaN layer for selective etching

We studied the patterning method of an ultra-thin GaN mask layer for selective growth and/or etching. Electron-beam (EB) irradiation effects with and without hot-jet Cl2 gas on the mask were examined. The Auger signal intensity of N was decreased to about 30% of the initial value by the EB-irradiation of1 × 1019electrons/cm2, revealing the electron-beam stimulated desorption (ESD) of GaN. We also studied the hot-jet Cl2 gas etching of GaN, which was assisted by this ESD, since hot-jet Cl2 is expected to be effective for completely removing GaN, owing to its high vibrational and translational energies. At a nozzle temperature of 760°C, where GaN was not etched only by hot-jet Cl2 gas, the GaN was almost completely removed by preirradiation of the EB. That is, the Auger signal of N was not detected in the EB-exposed area. The hot-jet Cl2 etching technique combined with EB is therefore promising for GaN mask patterning.