High-k Oxides on Hydrogenated-Diamond for Metal-Oxide-Semiconductor Field-Effect Transistors [Invited]

Abstract

Thanks to its excellent intrinsic properties, diamond is promising for applications of high-power electronic devices, ultraviolet detectors, biosensors, high-temperature tolerant gas sensors, etc. Here, an overview of high-k oxides on hydrogenated-diamond (H-diamond) for metal-oxide-semiconductor (MOS) capacitors and MOS field-effect transistors (MOSFETs) is demonstrated. Fabrication routines for the H-diamond MOS capacitors and MOSFETs, band configurations of oxide/H-diamond heterointerfaces, and electrical properties of the MOS and MOSFETs are summarized and discussed. High-k oxide insulators are deposited using atomic layer deposition (ALD) and sputtering deposition (SD) techniques. Electrical properties of the H-diamond MOS capacitors with high-k oxides of $\mathbf{ALD}-\mathbf{Al}_{2}\mathbf{O}_{3}, \mathbf{ALD}-\mathbf{HfO}_{2},\mathbf{ALD}-\mathbf{HfO}2/\mathbf{ALD}-\mathbf{Al_{2}O}_{3}$ multilayer, $\mathbf{SD}-\mathbf{HfO}_{2}/\mathbf{ALD}-\mathbf{HfO}_{2}$ bilayer, $\mathbf{SD-TiO_{2}/ALD-Al_{2}\mathrm{O}_{3}}$ bilayer, and ALD $\mathbf{TiO_{2}/ALD-Al_{2}O_{3}}$ bilayer are discussed. Analyses for capacitance-voltage characteristics of them show that there are low fixed and trapped charge densities for the $\mathbf{ALD}-\mathbf{Al}_{2}\mathbf{O}_{3}/\mathbf{H}$ -diamond and $\mathrm{SD}-\mathbf{HfO}_{2}/\mathbf{ALD}-\mathbf{HfO}_{2}/\mathbf{H}-$ diamond MOS capacitors. The k value of 27.2 for the $\mathbf{ALD-TiO_{2}/ALD-Al_{2}}\mathbf{O}_{3}$ bilayer is larger than those of the other oxide insulators. Drain-source current versus voltage curves show distinct pitch-off and p-type channel characteristics for the $\mathbf{ALD}-\mathbf{Al_{2}\mathrm{O}_{3}}/\mathbf{H}$ -diamond, SD- $\mathbf{EfO}_{2}/\mathbf{ALD}-\mathbf{HfO}_{2}/\mathbf{H}$ -diamon d, and $\mathbf{ALD}-\mathbf{TiO}_{2}/\mathbf{ALD}- \mathbf{A}1_{2}\mathbf{O}_{3}/\mathbf{H}$ -diamond MOSFETs. Understanding of fabrication routines and electrical properties for the high-k oxide/H-diamond MOS electronic devices is meaningful for the fabrication of high-performance H-diamond MOS capacitor and MOSFETs.