Influence of AlN buffer layer thickness on material and electrical properties of InAlN/GaN high-electron-mobility transistors

Wei Ching Huang, Kuan Shin Liu, Yuen Yee Wong, Chi Feng Hsieh, Edward Yi Chang*, Heng-Tung Hsu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

The influence of the thickness of a high-temperature AlN (HT-AlN) buffer layer on the properties of an InAlN/GaN high-electron-mobility transistor (HEMT) grown on a sapphire substrate was investigated. As revealed by atomic force microscope analysis, a rougher surface and larger grain size were observed with a thicker buffer layer. The larger grains promoted the two-dimensional (2D) growth mode of the GaN layer at the initial growth stage. This suppressed oxygen incorporation at the GaN/HT-AlN interface and thus improved the resistivity of the GaN layer. Moreover, the lower grain density also resulted in enhanced GaN crystal quality of the GaN layer. As a consequence, the electrical properties of the InAlN/GaN HEMT device, such as output current, transconductance and off-state breakdown voltage, were improved by increasing the HT-AlN buffer layer thickness.

Original languageEnglish
Article number071001
JournalJapanese Journal of Applied Physics
Volume54
Issue number7
DOIs
StatePublished - 1 Jul 2015

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