[18p-PA4-1~25] 6.2 Carbon-based thin films

△ [18p-PA4-22] Interface State Density Reduction of Diamond (111) MOS Structure and Channel Mobility Improvement of MOSFET by Hydrogen Plasma Treatment Introduction

〇(M2)Ukyo Sakurai¹, Tubasa Matsumoto¹, Masatsugu Nagai¹, HiromitsuKato Kato², Toshiharu Makino², Masahiko Ogura², Daisuke Takeuchi², Satoshi Yamasaki^1,2, Takao Inokuma¹, C. E. Nebel^1,3, Norio Tokuda^1,2 (1.kanazawa univ., 2.AIST, 3.Fraunhofer IAF)

Keywords:semiconductor, diamond, MOSFET

In recent years, our laboratory has realized the inversion layer channel diamond MOSFET. However, low channel mobility is an issue due to the high interface state density (D_it) ~10¹³ cm^-2 eV ^-1 at the MOS interface. Recent studies have shown that atomic smooth surfaces are roughened by acid treatment for Oxygen-termination and that the surface are atomically roughened. Anisotropic etching by hydrogen plasma treatment of the diamond surface has been identified to maintain an atomically flat surface.
In this study, after hydrogen plasma treatment of the diamond surface, we aim to reduce interface states by an OH termination process by using wet annealing treatment. Diamond (111) MOS capacitors and inversion layer channel diamond (111) MOSFETs were fabricated and their electrical characteristics were evaluated. In the MOS capacitor, the interface state density was reduced to the order of 10¹¹ cm^-2 eV^-1. In the MOSFET, the channel mobility was improved by an order of magnitude by the process of hydrogen plasma treatment.