An investigation of (NH4)2S passivation on the electrical, and interfacial properties of the Al2O3/GaSb system for p-type and n-type GaSb layers

Peralagu, U. , Povey, I.M., Hurley, P.K., Droopad, R. and Thayne, I.G. (2013) An investigation of (NH4)2S passivation on the electrical, and interfacial properties of the Al2O3/GaSb system for p-type and n-type GaSb layers. In: European Materials Research Society (EMRS 2013) Spring Meeting, Strasbourg, France, 27 - 31 May 2013,

Abstract

III-V materials have emerged as potential candidates to replace silicon in metal-oxide-semiconductor (MOS) devices for logic applications beyond the 15nm technology node. GaSb, in particular, offers a means to realizing a high-performance, low-power complementary logic solution owing to its high electron and hole mobilities. However, achieving a passivated, high-quality III-V/dielectric interface remains the biggest impediment to implementing a III-V logic solution. Among the various surface passivation strategies developed to engineer an improved interface, sulfur passivation ((NH4)2S) has been successful on GaAs and InGaAs. However, there is little discussion in the literature regarding this strategy on GaSb. In this work, we address the effectiveness of sulfur passivation, under differing (NH4)2S concentrations, on n-type and p-type GaSb MOS capacitors. The samples were chemically treated in 1%, 5%, 10% or 22% (NH4)2S solutions for 10 min at 295 K, prior to atomic-layer-deposition (ALD) of Al2O3. The capacitors were electrically and physically characterised using capacitance-voltage (C-V) measurements and transmission electron microscopy (TEM). Capacitors treated with 1% solution exhibited the largest capacitance modulation by the gate. The capacitance modulation and maximum accumulation capacitance decreased with increased (NH4)2S concentrations due to enhanced chemical etching of the GaSb surface resulting in degraded interface. Atomic force microscopy (AFM) further revealed the etching characteristics of GaSb in (NH4)2S as well as the etched surface roughness which are important when realizing GaSb transistors.

• Item Type: Conference Proceedings
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Thayne, Prof Iain and Peralagu, Mr Uthayasankaran
• Authors: Peralagu, U., Povey, I.M., Hurley, P.K., Droopad, R., and Thayne, I.G.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering