Bistable Defects Induced in GaAs by H2 Plasma Process

ABSTRACTWe have studied the effect of an H2 plasma (150 W; 150°C; 10, 20, 50, 100 s) on unannealed and annealed (850°C, AsH3 atmosphere) LEC GaAs material. Using Deep Level Transient Spectroscopy, we have shown that the plasma induces a main bistable defect DO, which has two possible stable states Dl and D2. A complete determination of the corresponding Configuration Coordinate Diagram has been done. Finally, no correlation has been obtained between DO and the native defects EL6, EL3 and EL2. No passivation of the EL2 defect has been observed and the evolution of the D0 concentration results from the association of hydrogen with AsGa. These observations are in disagreement with the identification of EL2 with an isolated AsGa.