Hydrogen and thermal deoxidations of InSb and GaSb substrates for molecular beam epitaxial growth

Abstract

Epitaxial growth on gas cluster ion-beam processed GaSb substrates using molecular-beam epitaxy

Atomic layer deposition of Al2O3 on GaSb using in situ hydrogen plasma exposure

“…The best performing samples exhibited the highest Ga-oxide content, implying that, rather than degrading electrical properties, interfacial Ga-oxide may serve to passivate defects at the semiconductor surface, as has been proposed for Al 2 O 3 /GaAs systems. 21 These XPS results are consistent with previous reports, 13,17,18 which suggest that hydrogen species decompose Sb-oxide present in the native film, resulting in the formation of elemental Sb and Ga-oxides. Elemental Sb is then removed by thermal desorption or by formation of volatile SbH 3 .…”

“…Elemental Sb is then removed by thermal desorption or by formation of volatile SbH 3 . 13 The generated Ga-oxide, is considerably more stable. Desorption of Ga-oxide has been reported at temperatures as low as 250 C when in the presence of a hydrogen plasma in ultra-high vacuum.…”

“…[7][8][9] As-grown GaSb surfaces are generally not suitable for direct ALD growth, as they possess thin native oxide layers that pin the Fermi-level at the insulator/semiconductor interface. As the thermal desorption temperatures of these oxides generally exceed 450 C, 13 wet etches are often employed to achieve a nearly oxide-free surface prior to ALD. Aqueous oxide removal treatments reported in conjunction with ALD on GaSb include: HCl, 7-12,14 (NH 4 ) 2 S, 14,15 NH 4 OH, 11,15 and HF.…”

Direct imaging of InSb (110)-(1×1) surface grown by molecular beam epitaxy

“…First, an Sb 4 flux of <0.5 monolayer per second (ML/s) was impinged on the InSb particles, after raising their temperature to $300 C. While maintaining the Sb 4 flux, the temperature was further increased to $450 C and held at the temperature for $20 min to thermally clean the InSb particles without using a hydrogen assist. 35 After reducing the temperature to $400 C, an InSb layer of 50-100 nm was epitaxially grown on the InSb particles by MBE. In and Sb 4 deposition rates were typically 0.1 and 0.2 ML/s, respectively, for the InSb epilayer growth.…”

Epitaxial growth of ZnTe on GaSb(100) using in situ ZnCl2 surface clean

“…Successful growth of ZnTe directly on GaSb substrates without the requirement for antimony stabilizing flux and GaSb buffer would considerably reduce the complexity of the material synthesis. For example, molecular or atomic hydrogen [11][12][13][14] has been used to deoxidize the GaSb surface without using an antimony overpressure flux, where high-quality ZnTe growth has been demonstrated following surface cleaning of GaSb with atomic hydrogen. 12 An alternative surface preparation technique for growing high quality ZnTe directly on GaSb substrates without a group-V stabilizing flux or any gas sources for surface preparation is presented in this work.…”