Thermal Diffusion Boron Doping of Single-Crystal Diamond

TL;DR

This paper introduces a novel low-temperature thermal diffusion method for doping single-crystal diamond with boron, enabling the fabrication of high-voltage electronic devices without damaging the crystal structure.

Contribution

It presents a simple, accessible doping strategy using heavily doped Si nanomembranes, overcoming previous challenges in SCD doping without causing lattice damage or graphitization.

Findings

Successful creation of doped SCD with activated boron atoms

Demonstration of high-voltage diodes and rectifiers using doped SCD

Atomistic simulations reveal a vacancy exchange doping mechanism

Abstract

With the best overall electronic and thermal properties, single crystal diamond (SCD) is the extreme wide bandgap material that is expected to revolutionize power electronics and radio-frequency electronics in the future. However, turning SCD into useful semiconductors requires overcoming doping challenges, as conventional substitutional doping techniques, such as thermal diffusion and ion implantation, are not easily applicable to SCD. Here we report a simple and easily accessible doping strategy demonstrating that electrically activated, substitutional doping in SCD without inducing graphitization transition or lattice damage can be readily realized with thermal diffusion at relatively low temperatures by using heavily doped Si nanomembranes as a unique dopant carrying medium. Atomistic simulations elucidate a vacancy exchange boron doping mechanism that occur at the bonded interface between Si and diamond. We further demonstrate selectively doped high voltage diodes and half-wave rectifier circuits using such doped SCD. Our new doping strategy has established a reachable path toward using SCDs for future high voltage power conversion systems and for other novel diamond based electronic devices. The novel doping mechanism may find its critical use in other wide bandgap semiconductors.