- 标题
- 摘要
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- 实验方案
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Gallium Oxide || MBE growth and characterization of gallium oxide
摘要： Gallium oxide (Ga2O3) is an ultrawide bandgap (UWBG) oxide semiconductor with an indirect bandgap of 4.5–5.2 eV. The beta-phase (β-Ga2O3) is the commonly regarded as most stable of the several crystalline phases (or polymorphs) of Ga2O3. Because of its wide bandgap, it is transparent from ultraviolet to visible wavelengths. It had first been widely explored as a transparent conductive oxide (TCO) for optical devices such as light-emitting diodes. Also, it has been used as a gate dielectric in metal oxide semiconductor (MOS) structures in GaAs. The β-Ga2O3 can be synthesized by melt growth techniques such as Czochraski, floating zone (FZ), and edge-defined film-fed growth (EFG) at atmospheric pressure which can provide inexpensive large area bulk substrates. The commercial availability of large area Ga2O3 substrates is an important advantage over GaN and similar group III-N compound semiconductors in many potential electrical and optical device applications. Besides material benefit of UWBG, these substrates provide a high-quality crystalline platform for power electronics devices that require higher crystalline quality, low-defect density material with precise doping control capabilities.
关键词： β-Ga2O3,MBE growth,Gallium oxide,ultrawide bandgap,heteroepitaxy,homoepitaxy
更新于2025-09-09 09:28:46
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Gallium Oxide || Properties of sputter-deposited gallium oxide
摘要： The wide bandgap oxides, such as ZrO2, Y2O3, HfO2, La2O3, Ga2O3, and GeO2, have been the focus of much attention in recent years due to their wide range of applications in optical, electronic and optoelectronic, photonic, and magnetoelectronic devices [1–12]. Gallium oxide (Ga2O3), one among these wide bandgap oxides, has been receiving recent attention of scientific and research community for its fascinating physical, chemical, and electronic properties, which can be readily utilized in numerous technological applications. Often quoted by several research groups, despite the great promise, properties and potential applications of these wide bandgap materials such as Ga2O3 have not yet fully explored.
关键词： optical properties,wide bandgap oxides,mechanical properties,Gallium oxide,sputter-deposited
更新于2025-09-09 09:28:46
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Gallium Oxide || Ohmic contacts to gallium oxide
摘要： The deposition of a metal onto a semiconductor surface to provide low contact resistance, high-reliability electrical contacts without adversely affecting the device during the metallization process is one of the most important challenges in device fabrication. Consequently, a fundamental understanding of how contacts work is essential for successful device manufacturing and commercialization. The physics of carrier transport across the metal-semiconductor junction renders metal contacts either rectifying (a.k.a. Schottky) or nonrectifying. A nonrectifying contact whose relationship between current and voltage has a low interfacial contact resistance Rc, and is preferably linear, is referred to as an Ohmic contact. Achieving low contact resistance Rc (Ω mm) or contact resistivity ρc (Ω cm2) has required a great amount of investigation for every relevant semiconductor material in the past. Typically, the successful formation of an Ohmic contact has relied on three constituent requirements: highly or degenerately doped semiconductor, choice of metallization, and thermal annealing. In the case of silicon, for instance, diffusion processes have been the topic of much early work but ultimately the control and reproducibility of ion implantation have rendered it an industry standard. For compound semiconductor heterostructure devices based on GaAs or GaN, the presence of a two-dimensional electron gas (2DEG) has necessitated a multilayer metallization deposition and annealing scheme, the details of which took many years to optimize. Particularly in the case of III-nitride high electron mobility transistors (HEMTs), Ohmic contacts were relatively easy to make on heteroepitaxal GaN due to its high dislocation density as the barrier height was reduced through defect-assisted formation of metal-nitride alloys during the anneal. Subsequent breakthroughs in GaN crystal growth, however, resulted in several orders of magnitude lower dislocation density homoepitaxial GaN, and naturally the contact resistance obtained under identical process conditions was higher [1]. Regrowth techniques to provide n+-doped GaN have become commonplace as a result.
关键词： thermal annealing,semiconductor,metallization,gallium oxide,contact resistance,Ohmic contacts
更新于2025-09-09 09:28:46
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Gallium Oxide || Power MOSFETs and diodes
摘要： Gallium oxide-based transistors and diodes possess fundamental electronic properties that make it an ideal candidate for high-power devices. A number of these properties derive directly from the wide bandgap of Ga2O3 (Eg ? 4.85 eV) including an exceptionally high electric breakdown field (approximately 8 MV/cm). This high breakdown field allows Ga2O3-based devices to be biased at a high drain voltage (Vbreak-down ? 100 V) while maintaining a large dynamic range. Furthermore, the wide bandgap of Ga2O3 allows device operation at elevated temperature (>300°C) without degradation. In addition, Ga2O3 has a high saturation electron velocity (vsat ? 2 (cid:2) 107 cm/s), which is partially accountable for the high current density, Imax (Imax (cid:3) qnvsat, where q ? 1.6 (cid:2) 10(cid:4)19 coulomb, n ? charge density, and vs ? electron saturation velocity). Despite the relatively low thermal conductivity of Ga2O3, the rapid development of high-quality native Ga2O3 substrates lowers the overall cost of production and avoids many of the defect-related issues that have hampered GaN and SiC devices. It is expected that Ga2O3-based devices will be competitive with Si-based medium-power as well as GaN and SiC-based high-power electronic devices.
关键词： Gallium oxide,high electric breakdown field,high saturation electron velocity,high-power devices,wide bandgap
更新于2025-09-09 09:28:46
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Graphene interdigital electrodes for improving sensitivity in Ga2O3:Zn deep-ultraviolet photoconductive detector
摘要： Graphene (Gr) has been widely used as a transparent electrode material for photodetectors due to its high conductivity and high transmittance, in recent years. However, the currently low-efficiency manipulation of Gr has hindered the arraying and practical use of such detectors. We invented a multi-step method of accurately tailoring graphene into interdigital electrodes, for fabricating a sensitive, stable deep-ultraviolet photodetector based on Zn-doped Ga2O3 films. The fabricated photodetector exhibits a series of excellent performance, including extremely low dark current (~10-11 A), ultra-high photo-to-dark ratio (>105), satisfactory responsivity (1.05 A/W) and excellent selectivity for DUV band, compared to those with ordinary metal electrodes. The raising of photocurrent and responsivity is attributed to the increase of incident photons through Gr, and separated carriers caused by the built-in electric field formed at the interface of Gr and Ga2O3:Zn films. The proposed ideas and methods of tailoring Gr can not only improve the performance of devices, but more importantly, it contributes to the practical development of graphene.
关键词： gallium oxide,photodetector,deep ultraviolet,graphene interdigital electrodes,ultralow dark current
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - Atlanta, GA, USA (2018.10.31-2018.11.2)] 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - Thermal and Thermomechanical Modeling to Design a Gallium Oxide Power Electronics Package
摘要： There is significant interest in the power electronics industry in transitioning from silicon to wide-bandgap devices. Gallium oxide devices have the potential to offer comparable or even superior performance than other wide-bandgap devices, but at a much lower cost. Recent breakthroughs include demonstration of a laboratory-scale gallium oxide transistors and diodes; however, a functional power electronics package for these devices is yet to be developed. In this paper, the research methodology in designing an electronics package for gallium oxide devices is outlined. Finite element-based thermal and thermomechanical modeling simulations were conducted to realize a package design that meets the combined target of minimal thermal resistance and improved reliability. Different package designs that include various material combinations and cooling configurations were explored, and their thermal and thermomechanical performance are reported. Furthermore, the short-circuit withstanding capabilities of gallium oxide devices were studied and compared with silicon carbide.
关键词： gallium oxide,thermal modeling,thermomechanical modeling,finite-element,high-temperature packaging,power electronics,wide-bandgap devices
更新于2025-09-04 15:30:14