Surface desorption properties of hydrogen-terminated diamond detected by micromechanical resonator

Abstract

Diamond, with its ultra-wide bandgap energy, has emerged as an extreme semiconductor due to its extraordinary electronic and thermal properties. The hydrogen-terminated diamond surface has attracted extensive attention due to its unique p-type surface conductivity. However, the fundamental nature of this p-type conductivity remains incompletely understood using existing surface analysis techniques. In this study, we investigate the dynamic thermal desorption of surface adsorbates on hydrogen-terminated diamond using single-crystal diamond microelectromechanical systems resonators, avoiding charging-related issues. By analyzing variations in resonance performance and surface conductivity, we uncover several key findings: (i) The desorption of surface adsorbates reaches saturation at approximately 873 K. (ii) The desorbed mass per unit area is around 2.3 fg/μm2, corresponding to an equivalent thickness of approximately 1 nm. (iii) The surface conductivity of hydrogen-terminated diamond can be fully restored even after annealing at 873 K, indicating the thermal stability of C–H bonds. This work offers an alternative insight into the surface properties of hydrogen-terminated diamond, accelerating the development of highly reliable diamond-based electronic devices.