Selectively buried growth of heavily B doped diamond layers with step-free surfaces in N doped diamond (1 1 1) by homoepitaxial lateral growth

Abstract

In this work, we proposed a novel method to form a buried heavily boron (B) doped p+-structure with a step-free diamond surface in nitrogen doped diamond (111) based on homoepitaxial lateral growth technique. The buried structure with a size of 10 µm × 10 µm × 0.085 µm was fabricated by inductively coupled plasma (ICP) etching of the mesa structure and subsequent heavy B-doping, with a boron to carbon (B/C) ratio of 15,000 ppm in the microwave-plasma-assisted chemical vapor deposition (MPCVD). The surface morphology of the buried area and its surrounding were observed by laser microscopy (LM) and atomic force microscopy (AFM), which showed atomically flat surfaces before and even after B doping. Surface potential difference measurements on both areas were applied using Kelvin-probe force microscopy (KFM). The intensity imaging of B concentration in and around the buried areas were measured by dynamic secondary ion mass spectrometry (SIMS), which confirmed the heavy B doping of the buried structure and the depth profile shows that B doping is uniform, with a concentration of 2 × 1020 atoms/cm3.