Characterization of pulsed laser deposited boron nitride thin films on InP

Abstract

A new technique for deposition of thin-film boron nitride (BN) from BN wafers has been demonstrated using a Q-switched ruby laser. The deposition rate was found to be ~7 Å/pulse at an energy density of 2.5 Jcm^-2. X-ray photoelectron spectroscopy was used to confirm the film composition. Infrared absorption peaks were observed at 802, 1370, and 1614 cm^-1 characteristic of B-N bonds. The films were found to have an indirect band gap of 4.1 eV with resistivity in excess of 10¹¹ Ωcm and breakdown fields between 3.0× 10⁵-1.0× 10⁶ Vcm^-1. The dielectric constant of the films was in the range 3.19-3.28. The minimum interface state density on InP as obtained from C-V (1 MHz) analysis was typically 6.2× 10¹⁰ cm^-2eV^-1, which increased to 4.1× 10¹¹ cm^-2eV^-1 after annealing at 200°C in argon. Scanning electron microscopy studies showed that this resulted in the development of micropores in the film.