Abstract

Correlation between chemical and electrical properties of n-InGaP surfaces grown by metal-organic chemical vapor epitaxy (MOVPE) was investigated by x-ray photoelectron spectroscopy (XPS), current-voltage (I-V) and UHV contactless capacitance-voltage (C-V) methods. An air-exposed surface exhibited highly In-rich phase where the InPO 4 -like natural oxide was dominant. Poor I-V characteristics appeared in Schottky contacts fabricated on the air-exposed surfaces. Chemical treatments in HCl and HF solutions were found to be effective in reducing natural oxide and in recovering the surface stoichiometry. The UHV contactless C-V results showed no pronounced Fermi level pinning at the chemically treated InGaP surfaces. Furthermore, such treatments improved Schottky I-V properties.