Optical and electrical properties of synthesized reactive rf sputter deposited boron-rich and boron-doped diamond-like carbon thin films

Abstract

Boron-doped diamond-like carbon (B-DLC) and boron-rich DLC thin films have been deposited on n-type silicon and quartz substrates by reactive rf magnetron sputtering process. Boron carbide (B4C) target was used in the deposition. Reducing the boron/carbon ratio was achieved by either using hydrogen gas or by introducing a proper flow rate of methane. Another approach of producing B-DLC thin films was achieved by using low methane\argon ratio (5/40) while sputtering atoms from non-saturated target-surface under various sputtering rf powers. The maximum film graphitization and lowest band gap energy was achieved by applying 100 W power. The Auger electron spectroscopy and Raman shifts were used to investigate the composition of the films. The optical properties were investigated using spectroscopic ellipsometry and spectrophotometer. Furthermore, p-type B-DLC/n-type Si(100) heterojunction diode was fabricated and the I–V characteristics were investigated against the flow rates of methane or the rf power.