Direct observation of species liberated from GaAs native oxides during atomic hydrogen cleaning

A real-time mass spectroscopic observation of liberated species was carried out to investigate the mechanism of atomic-hydrogen-( H•)-induced deoxidation of GaAs native oxides. Atomic hydrogen treatment at 410°C caused, initially, the liberation of molecular arsenic ( As 2 /As 4 ), resulting in the removal of As oxides, which was then followed by the liberation of Ga 2 O, leading to complete deoxidation. These results indicate that the deoxidation proceeds through two stages. The main chemical reactions are As 2 O x +2 x H•→ x H 2 O+ As 2 /(1/2As 4 ) in the first stage and Ga 2 O 3 + 4H•→2H 2 O+ Ga 2 O in the second stage.