Metal contacts to semiconductors, indium phosphide and cadmium telluride

We report several combinations of chemical preparation procedures for The surface preparation of I n P (100) substrates prior to epitaxial growth critically affects the formation of device compatible interfaces (INGREY et al.). Plane, smooth, and stoichiometrical surfaces free of any damage, of oxide and of chemical impurities (KURTH et al.) are needed for the growth of high quality epilayer on InP. Considerable literature exists describing the cleaning and oxidation of I n P surfaces (SCHWARTZ; NELSON et al.; HOLLINGER et al.). The problem t o obtain clean, defect-free I n P (100) surfaces is not satisfactorily solved (MASSIES et al.). The commonly used procedures as mechanochemical polishing, acid-or alkali etching followed by deionized water (DW) rinsing result in nonstoichiometric surfaces containig impure native oxides (INGREY et al.). Photoluminescence intensity (I~J,) studies (KRAWCZYK et al. ; SAU-TREUIL e t al.) and Schottky barrier measurements (SAUTREUIL et al.; ISMAIL et al.; WILLIAMS et al.) have shown that I n P is very sensitive to surface preparation.Any fresh prepared, oxide-free compound semiconductor surface storaged in any ambient will become contaminated (especially in air) and a rearrangement and diffusion of the surface atoms may result in nonstoichiometric surfaces. The removing or preventing of formation of contaminant layer is due in part t o the difficulty of removing carbon containing contaminants, their decomposition and the high stability of new formed ones (INGREY e t al.) (CONTOUR et al.). KURTII et al. found the possibility t o get oxide-free I n P surfaces in air, which are stable for the needed time of inserting the samples into the epitaxy apparatuses.

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