title: The effect of (NH4)2Sx passivation on the (311)A GaAs surface and its use in AlGaAs/GaAs heterostructure devices.
abstract: We have studied the efficacy of (NH4)2Sx surface passivation on the (311)A GaAs surface. We report XPS studies of simultaneously-grown (311)A and (100) heterostructures showing that the (NH4)2Sx solution removes surface oxide and sulfidizes both surfaces. Passivation is often characterized using photoluminescence measurements; we show that while (NH4)2Sx treatment gives a 40-60 ×  increase in photoluminescence intensity for the (100) surface, an increase of only 2-3 ×  is obtained for the (311)A surface. A corresponding lack of reproducible improvement in the gate hysteresis of (311)A heterostructure transistor devices made with the passivation treatment performed immediately prior to gate deposition is also found. We discuss possible reasons why sulfur passivation is ineffective for (311)A GaAs, and propose alternative strategies for passivation of this surface.
authors.affiliation: School of Physics, University of New South Wales, Sydney NSW 2052, Australia.
authors.forename: D J
authors.initials: DJ
authors.lastname: Carrad
authors.forename: A M
authors.initials: AM
authors.lastname: Burke
authors.forename: P J
authors.initials: PJ
authors.lastname: Reece
authors.forename: R W
authors.initials: RW
authors.lastname: Lyttleton
authors.forename: D E J
authors.initials: DE
authors.lastname: Waddington
authors.forename: A
authors.initials: A
authors.lastname: Rai
authors.forename: D
authors.initials: D
authors.lastname: Reuter
authors.forename: A D
authors.initials: AD
authors.lastname: Wieck
authors.forename: A P
authors.initials: AP
authors.lastname: Micolich