ROOM-TEMPERATURE UHV BONDING OF Si TO GaAs

摘要

The traditional method of wafer bonding at room temperature (RT) followed by high temperature annealing is not possible for bonding of Si to GaAs due to the difference in the thermal expansion coefficients of the two materials. Our bonding procedure consisted of ultrahigh vacuum (UHV) wafer bonding at room temperature without involving any intermediate layer. Silicon wafers were cleaned with standard RCA solution followed by dipping in diluted hydrofluoric acid. A UV/O_3 treatment was applied to the GaAs wafers in order to remove organic contamination. The native oxides were desorbed in-situ at 450℃. An atomic hydrogen induced modification of Ga_2O_3 into Ga_2O improved the process.rnElectrical properties of n-GaAs (100)/ p-Si (100) interfaces were investigated by temperature-dependent current-voltage (Ⅰ-Ⅴ) measurements correlated with deep level transient spectroscopy (DLTS) measurements. A high concentration of electrically active defects was observed at the interface, which decreased after annealing at 850℃.