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 p lasma chemistries (BCl3/SF6, BCl3/NF3, IBr, ICI, BI3, and BBr3) in a high d ensity plasma reactor. The normal etch stop reactions involving formation o f involatile AlF3, InF3, or InCl3 are found to be less effective under high density conditions because of the higher ion-assisted etch product desorpt ion 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 a chieved using the BI3 chemistry. (C) 1999 Elsevier Science B.V. All rights reserved.