Wet Chemical Etching of InP for Cleaning Applications

Abstract

The wet chemical etching of InP and its native oxide has been studied in HCl and H2SO4 solution to create oxide-free surfaces. The (100) InP surface is not etched in ≤2 M HCl and ≤6 M H2SO4. As the vetch <0.1 nm/min for these concentrations, the native oxide after OFOD treatment can be effectively removed without significantly etching the surface, as confirmed by contact angle measurements, ellipsometry and X-ray photoelectron spectroscopy. STM and AFM measurements showed that after OFOD treatment and subsequent oxide removal very smooth surfaces are achieved due to the creation of atomic terraces. The size of these terraces can be increased up to micron-size in 6 M H2SO4. Furthermore, it was shown that in presence of oxygen, n-type InP is photoetched/oxidized during wet processing. Last, the anisotropy in etching is discussed for InP in 2 M HCl and 2 M H2SO4.