Magnetron Enhanced Reactive Ion Etching of Group-III Nitride SemiconductorMaterials

摘要

Magnetron enhanced reactive ion etch rates of GaN, AlN, and InN wide bandgapsemiconductors were investigated as a function of cathode power, pressure, and flow rate in BCl3 plasmas. Etch rates were obtained which were significantly higher than previously reported for dry etching of these materials. Surface analysis of etched samples revealed the presence of boron and chlorine residues. Etching produced a gallium surface deficiency in GaN extending 10 nm below the surface, and a preferential loss of nitrogen in InN. Etch rates were determined for the ternary alloys In(0.25)Ga(0.75)N and In(0.75)Al(0.25)N as a function of the addition of H2, SF6, and Ar to BC13. In(0.25)Ga(0.75)N etch rates increased for additions up to 60% H2, 20% SF6 and 60% Ar concentrations in the gas mixtures, with higher additions producing a decrease in etch rates. For In(0.75)Al(0.25)N, etch rate increased slightly for Ar concentrations up to 40%, while H2 and SF6 additions reduced etch rates.