Plasma-activated direct bonding at room temperature to achieve the integration of single-crystalline GaAs and Si substrate

Abstract

We use a plasma-activated direct bonding process at room temperature to form heterostructures between GaAs and traditional Si substrates. The intermediate layer is not required at the bonding interface. The surface activation process is mainly carried out through inductively coupled Ar plasma for 60 s with surface bombardment. After activation, the oxide activity on the substrate surfaces is enhanced and the generation of defect states is inhibited. By using this process, a void-free and robust bonding GaAs/Si heterointerface can be realized. Additionally, the structure and element composition of the bonding interface are observed to understand the bonding mechanisms. It is confirmed that As, Ga, and Si elements diffuse each other at the interface. Finally, the electrical properties of GaAs/Si heterostructure are measured. This bonding method can be used in electronic, optical, mechanical and other fields to integrate single-crystalline GaAs onto Si platform.