Direct Bonding of Gallium Arsenide on Silicon

Abstract

Direct bonding of gallium arsenide on silicon is studied. The technology is expected to enable the easy integration of gallium arsenide optoelectronic devices with silicon very-large-scale integrated circuits. The interface quality of n-GaAs/p-Si can be improved with a thermal annealing process. It is examined by the current-voltage characteristics of the n-GaAs/p-Si diode. The bonding strength was found to be sufficiently high and could “high enough to” withstand the subsequent grinding and polishing procedures of the bonded wafers.

Nanobonding for Multi-Junction Solar Cells at Room Temperature

“…The subsequent annealing steps at 400 and 600 °C increased the forward current density. This behavior is different from that of the hydrophilic direct bonding of p-Si/nGaAs, where the forward current increased with increasing thermal annealing temperature [17]. The reverse leakage current density decreased as the annealing temperature increased.…”

“…In this study, while crystallinity at the bonded interface started at 400 °C and the amorphous layers vanished at 600 °C, no perfect crystalline structure was obtained at 600 °C. This can be explained by the diffusion mechanism stated in [17], but it requires further investigation to clarify the fact. Therefore, the reduced amorphous layer thickness upon annealing is responsible for the observed improvement of I-V characteristics from 200 °C to 600 °C.…”

“…Finally, at 600 °C, the amorphous layer diminished. Diffusion of Ga and As into Si has been hypothetically discussed through measuring the interfacial resistance of Si and GaAs bonded using the hydrophilic technique [17]. The diffusion increases with the increase of annealing temperature and time.…”