And have similar lattice constants to GaN, and may prove useful as substrates for III‐nitride epitaxy. We have found that these materials may be wet chemically etched in some acid solutions, including HF, at rates between 150 and 40,000 Å/min. Dry etching with plasmas provides faster rates than or under electron cyclotron resonance conditions, indicating the fluoride etch products are more volatile that their chloride or metallorganic/hydride counterparts.