Normally-off operating GaN-based pseudovertical MOSFETs with MBE grown source region

作者:Hentschel Rico*; Schmult Stefan; Wachowiak Andre; Grosser Andreas; Gaertner Jan; Mikolajick Thomas
来源:Journal of Vacuum Science and Technology B, 2018, 36(2): 02D109.
DOI:10.1116/1.5017291

摘要

In this report, the operation of a normally-off vertical gallium nitride (GaN) metal-oxide field effect transistor with a threshold voltage of 5V is demonstrated. A crucial step during device fabrication is the formation of the highly n-doped source layer. The authors infer that the use of molecular beam epitaxy (MBE) is highly beneficial for suppressing diffusion of the magnesium (Mg) p-type dopants from the body layer grown by metal-organic vapor phase epitaxy into the source cap. Repassivation of the previously activated Mg acceptors by a hydrogen out-diffusion treatment is suppressed in the ultrahigh vacuum growth environment. Structural and electrical data indicate that the defect density of the GaN substrate is currently limiting device performance much more compared to other effects like varying surface morphology resulting from fluctuations in III/N stoichiometry during the MBE growth. Published by the AVS.

  • 出版日期2018-3

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