Stability of diamond/Si bonding interface during device fabrication process

Diamond/Si bonding interface with an entire contact area and high thermal stability is achieved by surface activated bonding method. The fabrication of diamond field-effect transistors (FETs) on the diamond bonded to Si is demonstrated. The FET exhibits clear saturation and pinch-off characteristics. A 5 nm thick SixCx-1 layer was formed at the interface with annealing at 1000 °C. The layer was formed by the inter-diffusion of carbon and Si atoms near the bonding interface, which plays a role of residual stress relaxation between diamond and Si. These results suggest that diamond/Si heterostructures are applicable for combining diamond devices with Si LSI.