New plasma chemistries for etching III-V compound semiconductors: BI3 and BBr3

We investigated inductively coupled plasma (ICP) etching of both In-contain ing (InP, InAs, and InSb) and Ga-containing compound semiconductors (GaAs, GaP, and GaSb) in two new chemistries: BI3 and BBr3 with addition of Ar. Et ch rates as high as 2 mu m . min(-1) were obtained for InP in both types of discharge while for GaAs maximum rates were 1 and 2.5 mu m . min(-1), resp ectively in BI3 and BBr3. The rates were strongly dependent on plasma compo sition, ICP source power and radio frquency chuck power. BI3 etching produc ed much smoother surfaces on both GaAs and InP, while maintaining the near- surface stoichiometry. Etch selectivities greater than or equal to 10 were obtained for GaAs and InP over SiO2 and SiNx masks. The BI3 chemistry appea rs attractive as an universal etchant for In-based and Ga-based compound se miconductors.