Selective dry etching using inductively coupled plasmas Part I. GaAs AlGaAs and GaAs InGaP

Selective etching of GaAs over AlGaAs and InGaP was examined in different plasma chemistries (BCl3/SF6, BCl3/NF3, IBr, ICI, BI3, and BBr3) in a high density plasma reactor. The normal etch stop reactions involving formation of involatile AlF3, InF3, or InCl3 are found to be less effective under high density conditions because of the higher ion-assisted etch product desorption efficiency. Addition of SF6 to BCl3, produces higher selectivities than NF3 as an additive, while IBr, ICI and BBr3 are essentially non-selective for both heterostructure systems. Selective etching of InGaP over GaAs is achieved using the BI3 chemistry. (C) 1999 Elsevier Science B.V. All rights reserved.