-10 V Threshold Voltage High-Performance Normally-OFF C-Si Diamond MOSFET Formed by p+-Diamond-First and Silicon Molecular Beam Deposition Approaches

In this article, the normally-OFF oxidized Si-terminated ( C-Si) diamond metal-oxide-semiconductor field-effect transistors (MOSFETs) with as-deposited 0.5-nm siliconon diamond annealed at high temperature as the subsurface p-channel were presented for the first time. A novel method utilizing both a metal mask to realize the regrown heavily boron-doped (001) diamond layer first (p(+)-diamond-first) and a molecular beam deposition (MBD) method to procure atomic-scale silicon deposition was achieved. Scanning transmission electron microscopy ( STEM) and energy-dispersive X-ray spectroscopy (EDS) element mapping results suggest that the C-Si diamond/Al2O3 interface is quite continuous and atomically flat. A remarkably high threshold voltage (VTH) of -10 V and a maximum drain current density (I-D_MAX) of -156mA/mmare simultaneously achieved in the fabricated devices. The devices with different source and drain (S/D) distances (LSD) deliver robust VTH results and feature low OFF-state S/D leakage current vertical bar I-leakage vertical bar of similar to 6 x 10(-6) mA/mm at V-GS = 0 V. The extracted field-effect mobility is as high as 127 cm(2).V-1.s(-1) and the interface state density is as low as 4.35 x 10(12) eV(-1).cm(-2). These competitive results reveal that this first attempt of employing the combination of p(+)-diamond-first and MBD approaches promotes the integration of the advanced silicon manufacturing process with wide bandgap diamond material for power applications.

Automated summary

This article presents a novel approach to integrate the advanced silicon manufacturing process with wide bandgap diamond material for power applications. By utilizing a metal mask and molecular beam deposition method, the researchers successfully achieved oxidized Si-terminated (C-Si) diamond MOSFETs with a subsurface p-channel. The fabricated devices demonstrated high performance with a remarkably high threshold voltage and maximum drain current density.