An investigation of the growth and removal of protective antimony caps for antimonide epilayers

We present a surface X-ray diffraction and Auger electron spectroscopy investigation of antimony capping layers used to protect indium antimonide and gallium antimonide epilayers. A thermally induced amorphous to polycrystalline structural transition was observed at approximately 190 °C for Sb caps on InSb(0 0 1) and GaSb(0 0 1) substrates. We conclude that 100 nm Sb caps deposited at elevated substrate temperature (150–200 °C) have superior structural order, and are able to protect III-Sb epilayers from atmospheric contamination for periods of at least a year.