MOSFETs on (110) C–H Diamond: ALD Al₂O₃/Diamond Interface Analysis and High Performance Normally-OFF Operation Realization

Hole concentration of 2-D hole gas (2DHG) on (110) diamond is higher than that on other faces, making it the best choice for power device application. Detailed analysis of atomic layer deposition (ALD) Al₂O₃/(110) C–H diamond interface structure is of vital importance. MOSFETs with thin (10 nm) and thick (100 nm) ALD Al₂O₃ layer were made in this study. The microstructure of Al₂O₃ on (110) C–H diamond was analyzed. Abrupt interface of ALD Al₂O₃/C–H diamond was observed through high resolution transmission electron microscope (HRTEM). Cascode structure using diamond MOSFETs and enhancement mode silicon MOSFET is fabricated and its high performance is confirmed.