GaN focused ion beam micromachining with gas-assisted etching

Abstract

Halide gases, such as Cl2, IBr, or ICl, are common etchant species for the etching of III nitrides and other compound semiconductor materials in plasma etching processes. We have investigated the Ga+ focused ion beam milling of GaN in conjunction with gas-assisted etching (GAE) by halide gases I2 and XeF2. We have observed that I2 and XeF2 GAE with a 30 keV Ga+ ion beam leads to significantly enhanced GaN etch rates. When these gases are utilized with appropriate ion beam scan strategies (such as ion beam current, beam dwell time, and beam overlap), we have measured GaN etch rate enhancements of 6× to 9× and 2× to 3× faster for I2 and XeF2, respectively.