Advances in pulsed laser deposition of nitrides and their integration with oxides

Abstract

Pulsed laser deposition (PLD) is emerging as the fastest thin film prototyping tool for a variety of multicomponent ceramic films. There could be significant payoffs in applying this technique for the growth of GaN and related wide bandgap semiconductor films and heterostructures (primarily for their potential applications in optoelectronics and high-temperature high-power electronics), on account of PLD's speed and flexibility. The present work describes the pulsed laser deposition of GaN and other participating electronic and optoelectronic materials such as AlN, TiN, and ZnO on sapphire. A pulsed KrF excimer laser was used for ablation of the sintered stoichiometric GaN, AlN, and TiN targets. The processing parameters such as laser fluence, substrate temperature, background gas pressure, and pulse repetition rate have been optimized for growth of high-quality epitaxial films. The films were characterized by X-ray diffraction, Rutherford backscattering spectrometry, ion channeling, high-resolution transmission electron microscopy, atomic force microscopy, UV–visible spectroscopy, and electrical resistivity measurement. We also discuss pulsed laser deposition of multilayer heterostructures of TiN/AlN/TiN (as capacitors for high-temperature electronics), ZnO heteroepitaxy and its integration with GaN for fabrication of novel devices.