Epi-Gd2O3/AlGaN/GaN MOS HEMT on 150 mm Si wafer: A fully epitaxial system for high power application

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Researchers

Research units

  • Indian Institute of Technology, Bombay
  • Leibniz Universität Hannover

Abstract

In this letter, we report the impact of epitaxial Gd2O3 on the electrical properties of an AlGaN/GaN high electron mobility transistor (HEMT) grown on a 150 mm diameter Si (111) substrate. Incorporation of epitaxial Gd2O3 grown by the molecular beam epitaxy technique under a metal gate (metal/Gd2O3/AlGaN/GaN) causes six orders of magnitude reduction in gate leakage current compared to metal/AlGaN/GaN HEMT. We observe that epi-Gd2O3 undergoes complete structural changes from hexagonal to monoclinic as the thickness of the layer is increased from 2.8 nm to 15 nm. Such structural transformation is found to have a strong impact on electrical properties whereby the gate leakage current reaches its minimum value when the oxide thickness is 2.8 nm. We find a similar trend in the density of interface traps (Dit) having a minimum value of 2.98 × 1012 cm-2 eV-1 for the epioxide layer of thickness 2.8 nm. Our measurements also confirm a significant increase in the two dimensional electron gas (2DEG) density (∼40%) at AlGaN/GaN interface with epioxide grown on AlGaN, thus confirming the contribution of epitaxial lattice strain on 2DEG modulation.

Details

Original languageEnglish
Article number063502
JournalApplied Physics Letters
Volume115
Issue number6
Publication statusPublished - 5 Aug 2019
MoE publication typeA1 Journal article-refereed

ID: 36261574