Formation of p-Type Ultrananocrystalline Diamond/Nonhydrogenated Amorphous Carbon Composite Films Prepared by Coaxial Arc Plasma Deposition with Boron-Incorporated Graphite Targets

Abstract

Boron-doped ultrananocrystalline diamond (UNCD)/nonhydrogenated amorphous carbon (a-C) composite (UNCD/a-C) films were prepared by coaxial arc plasma deposition (CAPD) with boron-blended graphite target. Their growth was achieved at room temperature and a base pressure of less than 10-3 Pa (no inflow gas) owing to CAPD, whereas the growth of UNCD films by chemical vapor deposition generally requires high substrate temperatures of more than 700°C and a hydrogen ambient gas. The formation of p-type conduction was confirmed thermally, namely Seebeck effect, and heterojunction diodes formed with n-type Si exhibited a typical rectifying action. It was demonstrated that CAPD is advantageous to the practical film formation including doping.