β‐Gallium Oxide Devices: Progress and Outlook

Abstract

Beta‐gallium oxide (β-Ga2normalO3) has a history of research and development for over 70 years; however, it has attracted little attention as a semiconductor material for a long time. The situation has drastically changed in the past decade, and research on its material properties and developments of growth and device technologies has become active worldwide, mainly from expectations for applications to next‐generation power devices. Most of the specific material properties are attributed to its extremely large bandgap energy of 4.5 eV. The other important material feature is that large‐size single‐crystal bulks can be synthesized by melt growth methods. Herein, after introducing the material properties of β-Ga2normalO3 that are important for electronic devices, the current status of bulk melt growth and epitaxial thin‐film growth technologies is given. State‐of‐the‐art β-Ga2normalO3 diodes and transistors are also discussed, including future prospects.

Gallium Oxide Nanostructures: A Review of Synthesis, Properties and Applications

“…Another factor that defines the usage of gallium oxide in higher power devices is Baliga's Figure of Merit (BFOM) [55,195,196]. BFOM ∝ εμEc 2…”

Growth characteristics and properties of Ga2O3 films fabricated by atomic layer deposition technique

“…89 The crystal phases of ALD-grown Ga 2 O 3 films can also be identified by the XRD spectrum. 65,68 Roberts et al prepared a-Ga 2 O 3 on sapphire using TEG and O 2 plasma, for which the XRD peak at 40.04831 corresponds to the a-Ga 2 O 3 (0006) reflection, and additional weak peaks corresponding to b-Ga 2 O 3 (3)(4)(5)(6)(7)(8)(9)(10)(11), e-Ga 2 O 3 (0004), and e-Ga 2 O 3 (21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31) were distinguished. 94 The crystalline quality of ALD-deposited Ga 2 O 3 films could be assessed by measuring the full-width-at-half-maximum (FWHM) of the rocking curve o scans taken on symmetric and skew-symmetric reflections.…”

“…9 Herein, Ga 2 O 3 shows high-efficiency performance as a power device channel for lower specific on-resistance at a high breakdown voltage and then delivers higher power but less consumption. 10–18 Moreover, the absorption cut-off wavelength of Ga 2 O 3 is in the deep ultraviolet range of 260–280 nm; thus, it can be used to fabricate solar-blind photodetectors without the need of complex alloying processes such as Zn x Mg 1− x O and Al x Ga 1− x N. 19–27 Ga 2 O 3 also has high dielectric constant, high optical transparency, excellent chemical and thermodynamic stability, and can be applied as transistor gate dielectrics and passivation layers, in high temperature gas sensing, transparent conducting oxides, solar cells, light-emitting diodes, in the detection of nuclear radiation, etc. 28–34…”

“…9 Herein, Ga 2 O 3 shows high-efficiency performance as a power device channel for lower specific on-resistance at a high breakdown voltage and then delivers higher power but less consumption. [10][11][12][13][14][15][16][17][18] Moreover, the absorption cut-off wavelength of Ga 2 O 3 is in the deep ultraviolet range of 260-280 nm; thus, it can be used to fabricate solar-blind photodetectors without the need of complex alloying processes such as Zn x Mg 1Àx O and Al x Ga 1Àx N. [19][20][21][22][23][24][25][26][27] Ga 2 O 3 also has high dielectric constant, high optical transparency, excellent chemical and thermodynamic stability, and can be applied as transistor gate dielectrics and passivation layers, in high temperature gas sensing, transparent conducting oxides, solar cells, light-emitting diodes, in the detection of nuclear radiation, etc. [28][29][30][31][32][33][34] Ga 2 O 3 thin films could be prepared by various deposition techniques such as molecular beam epitaxy (MBE), halide vapor phase epitaxy (HVPE), metal organic chemical vapor deposition (MOCVD), pulsed laser deposition (PLD), magnetron sputtering, thermal evaporation, and atomic layer deposition (ALD).…”

A Comprehensive Review on Recent Developments in Ohmic and Schottky Contacts on Ga2O3 for Device Applications

“…In the past decade, gallium oxide Ga 2 O 3 has emerged as a challenger for this task with the successful demonstration of power transistors due to the possibility of growing large high-quality singe crystals. Already Ga 2 O 3 based diodes and transistors with 1–3 kV breakdown voltages have been demonstrated as mentioned in Table . − …”