ICP-RIE dry etching using Cl2-based on GaN

摘要

In this study, the plasma characteristics and GaN etch properties of inductively coupled Cl2/Ar and Cl2/H2 plasmas wereudinvestigated. Our results showed that inductively coupled plasma (ICP) etching of gallium nitride by using Cl2/Ar andudCl2/H2 were possible to meet the requirements (anisotropy, high etch rate and high selectivity). We have investigatedudthe etching rate dependency on the percentage of argon and hydrogen in the gas mixture and the DC voltage. Surfaceudmorphology of the etched samples was checked by SEM and AFM. It was found that the etched surface was anisotropicudand the smoothness of the etched surface is comparable to that of polished wafer. As results, gas mixture using Cl2/Ar,udwe obtained highest etching rates; 5000 Å/min and ~0.5 nm rms roughness for n-GaN and for p-GaN, the etching ratesudwas 3300 Å/min and ~0.7 nm for rms roughness. Meanwhile, for gas mixture using Cl2/H2, the etching was 1580 Å/minudfor n-GaN and 950 Å/min for p-GaN.