Abstract
High-voltage Schottky barrier diodes (SBDs) are fabricated on 4H-SiC epitaxial layers obtained at a high growth rate (14_??_16μm/h). The epitaxial layers are grown in a vertical radiant-heating reactor, with pre-growth and growth conditions controlled to reduce morphological defects. A good morphology with a low density of growth pits is achieved by applying to substrates pre-growth hydrogen etching under reduced pressure down to 4000Pa. Two types of edge termination structures, B-implanted termination and junction termination extension (JTE), were tested for use in fabricating high-voltage 4H-SiC SBDs. A high blocking voltage of 1.2kV was achieved when using a 10μm-thick layer by applying B-implanted termination, despite the layer being grown in only 40 minutes. When using 27pm-thick epitaxial layers, a 2.4kV-9.1 mΩcm2 SBD with B-implanted termination and 3.4kV-16.0 mΩcm2 SBD with JTE were successfully fabricated. We also succeeded in obtaining a 4 mmφ diode with an allowable leakage current, and a high yield rate exceeding 90% for the 1 mmφ diodes.
