Newly developed passivation of GaAs surfaces and devices

In addition to the established methods, we have developed three new passivation techniques. The first one is the electrochemical sulfur passivation, which can create a thick S-containing layer on the top of GaAs substrate. The thick passivation layer can prevent the GaAs surface being reoxidized in air, and thus the stability is greatly improved. The second passivation technique uses an oxygen-free sulfur-containing solvent-S₂Cl₂. It can remove the oxides of GaAs very effectively and create a S-terminated surface. The third technique is to form a thick GaS overlayer on the top of GaAs by using S glow discharge (SDG). The preliminary results seem to be quite encouraging. It might be possible to eventually solve the problem of surface passivation for GaAs and related III-V compound semiconductors