GaAs surface cleaning by low energy hydrogen ion beam treatment

Abstract

A technology of semiconductor surface cleaning has been applied to GaAs surfaces for the preparation of contamination free surfaces. This technique combines a low energy hydrogen ion beam (ion energy <500 eV) with an increased substrate temperature (150 °C). The long term change of the GaAs (001) surface composition under the influence of this process was investigated with in situ x-ray photoelectron spectroscopy and atomic force microscopy. A removal of surface oxides and carbon as well as of surface contaminations due to the hydrogen ion beam treatment could be observed. At an elevated substrate temperature of 150 °C, the hydrogen ion beam produces a contamination-free surface without changes in surface composition (stoichiometry) or surface roughness, whereas room temperature hydrogen exposure results in an As-depleted surface composition. This technique could be used for wafer direct bonding of III–V semiconductors and other processes which require highly efficient quality cleaning procedures.