MOSFETs on (110) C–H Diamond: ALD Al₂O₃/Diamond Interface Analysis and High Performance Normally-OFF Operation Realization
Benjian Liu, Te Bi, Yu Fu, Ken Kudara, Shoichiro Imanishi, Kang Liu, Bing Dai, Jiaqi Zhu, Hiroshi Kawarada
Abstract
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) Al<sub>2</sub>O<sub>3</sub>/(110) C–H diamond interface structure is of vital importance. MOSFETs with thin (10 nm) and thick (100 nm) ALD Al<sub>2</sub>O<sub>3</sub> layer were made in this study. The microstructure of Al<sub>2</sub>O<sub>3</sub> on (110) C–H diamond was analyzed. Abrupt interface of ALD Al<sub>2</sub>O<sub>3</sub>/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.