The dawn of Ga2O3 HEMTs for high power electronics - A review

R. Singh, T. R. Lenka, D. K. Panda, R. T. Velpula, B. Jain, H. Q.T. Bui, H. P.T. Nguyen

Research output: Contribution to journalReview articlepeer-review

4 Scopus citations

Abstract

Recently, there is a growing interest in Gallium Oxide (Ga2O3) as a promising semiconductor material for intended applications in RF, power electronics, and sensors with high capabilities over existing technologies due to its excellent material characteristics like large bandgap, well-controlled doping, and availability of large size inexpensive substrates. Bulk crystals of monoclinic β-Ga2O3 can be grown using melt growth techniques, which ensures large, uniform substrates with relatively low-cost per wafer as compared to GaN and SiC substrates which are usually grown using vapor growth techniques. A large critical field of β-Ga2O3 is beneficial for improving the DC performance of high voltage rectifiers and metal oxide semiconductor field-effect transistors (MOSFETs) and facilitates further lateral scaling of FETs for improved RF performance. Band structure of β-Ga2O3 indicates difficulty in p-type conductivity, so previously reported most of the β-Ga2O3 MOSFETs have been depletion mode, although enhancement mode operations were also demonstrated using recess-gate and charge-trapping gate stack structure. The β-Ga2O3 heterostructures have been widely reported using a high-quality epitaxial layer of β-(AlxGa1−x)2O3 after alloying Al with Ga2O3. The β-Ga2O3 modulation-doped FETs (MODFETs) have shown two-dimensional electron gas (2DEG) density of ~1012 cm−2 that form a good quality channel at the interface. Despite low room temperature electron mobility of around 180 cm2 V−1s−1, peak mobility of around 2800 cm2 V−1s−1 at 50 K was measured in the latest reported experimental work of β-Ga2O3 MODFET. III-nitride based GaN high electron mobility transistors (HEMTs) have been widely used in high power electronics and have shown 2DEG density ~ 1013 cm−2 and channel mobility of 2000 cm2 V−1s−1. This paper gives a perspective of Ga2O3 material towards making high electron mobility transistors (HEMTs) for a certain class of RF applications. Due to low in-plane lattice mismatch, a high-quality epitaxial layer of GaN and AlN have been grown on β-Ga2O3. Furthermore, due to the inherent polarization property of III-nitrides and large bandgap, higher 2DEG density ~1013 cm−2 and large conduction band offset >1.5 eV can be expected in AlN/β-Ga2O3 heterostructure. The various defects in WBG devices and their effects on the reliability aspects are also addressed.

Original languageEnglish (US)
Article number105216
JournalMaterials Science in Semiconductor Processing
Volume119
DOIs
StatePublished - Nov 15 2020

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Keywords

  • 2DEG
  • GaO (gallium oxide)
  • HEMT
  • III-Nitride
  • Polarization
  • Thermal conductivity

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