Review—RF Sputtered Films of Ga₂O₃

Abstract

Ga2O3 has been a subject of interest in research field with varying applications for current and future generation electronic devices. Due to its ultra-wide bandgap of 4.5–5.0 eV, extremely high BFOM of 3444, and other prominent characteristics relating to material properties, easy to mass-produce and economical, β-Ga2O3 finds applications in variety of electronics devices, power devices and optoelectronics devices. A comprehensive review of RF sputtered β-Ga2O3 films along with its properties, studies and applications are presented in this paper for the first time. Polymorphs of gallium oxide and crystal structure are discussed. Structural and chemical composition studies are reviewed with XRD and XPS. This review summarizes the recent progress in effects of sputtering parameters on film properties of Ga2O3. This review provides an in-depth analysis of mechanical, optical, film morphology, electrical properties of RF sputtered β-Ga2O3 films. The role of sputtering parameters such as substrate temperature, sputtering power, annealing temperatures and oxygen composition in the reactive sputtering for crystallinity are discussed. Furthermore, doping elements effects on bandgap changes are reported.

Application-Specific Oxide-Based and Metal–Dielectric Thin-Film Materials Prepared by Radio Frequency Magnetron Sputtering

“…Sputtering processes allow thin-film materials to be deposited either on bare substrates or on top of any structured systems, e.g., photonic or magneto-photonic crystals, usually without having any unpredictable thickness uniformity or stoichiometry issues with the grown films. Thin-film materials, especially radio frequency (RF) magnetron-sputtered thin films, were originally considered useful mainly in electronics and semiconductor devices; however, sputtered thin films have also been found to be applicable within a wide range of fields, such as optoelectronics, energy, mechanical/chemical, optical coatings, life sciences, and others [9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30]. In this nanotechnological era, the sputter deposition of thin films becomes a rather ubiquitous and actively growing field of human endeavour, integrating the fundamental and important scientific areas of research, process development, deposition system design, and new product manufacturing.…”

Oxygen Sensors Based on Thin Films of Gallium Oxide Modified with Silicon

“…Stoichiometric Ga2O3 possess an O/Ga ratio of 1.5. The O/Ga ratio in Ga2O3 films depends on the sputtering conditions [13]. It should be noted that the obtained films of the pure Ga2O3 were close to stoichiometric.…”

Recent Progress of Deep Ultraviolet Photodetectors using Amorphous Gallium Oxide Thin Films

“…Sputtering, as a well‐developed thin‐film deposition technique, has been widely applied to produce thin films in industry with advantages such as simple apparatus, low deposition temperature, high deposition rate, and good adhesion along with uniformity and suitability for large area deposition. [ 38 ] As Ga 2 O 3 target is usually nonconductive due to its ultralarge bandgap, it can only be prepared using RF source. Saikumar et al has summarized recent results related with RF‐sputtered β‐Ga 2 O 3 thin films, from which we can see many factors including substrate temperature, working pressure, oxygen partial pressure, RF power can affect the characteristics of the films.…”

“…Saikumar et al has summarized recent results related with RF‐sputtered β‐Ga 2 O 3 thin films, from which we can see many factors including substrate temperature, working pressure, oxygen partial pressure, RF power can affect the characteristics of the films. [ 38 ] Considering the aforementioned factors, a table has been made related with RF‐sputtered a‐GaO x materials ( Table 1 ), where some typical features can be outlined.…”