Low-Energy Ion-Assisted Deposition of Boron Nitride Films in Surface-Wave Plasma

Abstract

A surface-wave plasma operated at 2.45-GHz microwave (MW) is used to deposit hexagonal boron nitride (hBN) films by applying a negative or positive bias voltage to a substrate. Ion energy and flux onto the substrate are examined in terms of MW power, pressure, substrate location, and substrate bias. The mean ion energy is estimated from the sheath potential measured with a Langmuir probe and controlled between a few electronvolts and ~170 eV. hBN films are deposited on silicon in a gas mixture of He, N₂, H₂, and BFN₃ by varying either the ion energy or substrate temperature under a high ion flux condition (1017 cm−2s−1). The results show that the crystallinity of sp2-bonding network in the films depends upon ion energy more than substrate temperature.