Characterization of oxide desorption from InSb(001) substrates

Abstract

Thermal desorption of oxide layers from InSb(001) substrates was studied using reflection high energy electron diffraction (RHEED), x-ray photoelectron spectroscopy, Auger electron spectroscopy, and scanning electron spectroscopy. Surfaces of as-loaded substrates prepared using either of two common chemical etchants were composed of oxide layers containing In2O3 and Sb2O5. As the substrate temperature was raised, a multistage desorption process was observed. Most of the Sb2O5 was reduced during the first stage, leaving behind a thin oxide layer consisting predominantly of In2O3. In2O3 was desorbed during the second stage, as the substrate temperature was raised further in the presence of an Sb flux. Indium droplets condensed on the surface before a smooth morphology ensued. We suggest that the reduction of In2O3 produced In droplets which reacted with the supplied Sb flux to form InSb. Annealing produced smooth, stoichiometric surfaces that gave rise to well-defined, Sb-stabilized pseudo-(1×3) RHEED patterns. InSb films grown on such substrates exhibited good structural and electrical properties.

Plasma-Cleaned InSb (112)B for Large-Area Epitaxy of HgCdTe Sensors

“…These binding energies represent the measured energy positions of In and Sb in a stoichiometric InSb material system. The spin-orbit separation and biding energies are in close agreement with those reported by Liu and Santos, 30 who presented detailed XPS, with binding energies, chemical shifts, and Auger spectra obtained from InSb after chemical preparation and during thermal desorption. The composition of the plasma-cleaned InSb (112)B surface was calculated using a standard procedure where a Shirley background subtraction and a five-point smoothing was first applied to the data.…”

“…35 Defects expected from In-Te compound formation are suppressed on the B face 36 without using a Cd overpressure. 35 As such, the observed defects may be attributed to thermal 11,30,37,38 or plasma sputter 37 induced microscopic In islands which may lead to hillock-like growth features. 11 As the relaxed lattice mismatch (Da/a) is small, 0.05%, 36 and a portion is elastically accommodated, 39 low EPD and narrow x-ray diffraction rocking curves are expected.…”

“…11,29,[30][31][32] Although these combinations were not optimized, the best results were obtained by etching the InSb (112)B wafer with lactic acid:nitric acid (10:1) (it should be noted that in this case the lactic acid: HNO 3 :HF at 25:4:1 etch was not included), then exposing the wafer to an H + /Ar + plasma 26,33 followed by annealing at 375°C under Sb flux. Figure 1 shows the RHEED pattern of an InSb (112)B substrate thus prepared.…”

Physical and Chemical Methods for Thin-Film Deposition and Epitaxial Growth

“…A detailed series of experiments have been reported using a variety of etches and microscopic analysis of post-etch morphology as well as XPS, RHEED, and AES studies of the surface before, during, and after oxide desorption. (69,70) They found that the etch CP4A (HNO 3 :CH 3 COOH:HF:H 2 O in the ratio 2:1:1:10) produces the flattest surfaces. The surfaces are also protected by a passivating oxide produced by the oxidizing etch.…”

Chemical analysis of a sulfur‐treated InSb(111)A surface by XPS

“…[6] It was found that the sulfur treatment of an InSb(100) surface prior to insulator layer deposition results in considerable reduction of the surface charges and improves thermal stability of the performance of metal-insulator-semiconductor devices. [7,8] The surface treatment with an ammonium sulfide solution caused notable photosensitivity enhancement and dark current reduction for InAsSb and InAsPSb photodiodes.…”