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http://dx.doi.org/10.5573/ieie.2014.51.2.033

Improved Characteristics in AlGaN/GaN-on-Si HFETs Using Sacrificial GaOx Process  

Lee, Jae-Gil (School of Electronic and Electrical Engineering, Hongik University)
Cha, Ho-Young (School of Electronic and Electrical Engineering, Hongik University)
Publication Information
Journal of the Institute of Electronics and Information Engineers / v.51, no.2, 2014 , pp. 33-37 More about this Journal
Abstract
We have developed a novel passivation process employing a sacrificial gallium oxide process in order to recover the surface damage in AlGaN/GaN HFETs. Even with a conventional prepassivation process, surface damage during high temperature ohmic annealing cannot be avoided completely. Therefore, it is necessary to recover the damaged surface to avoid the characteristic degradation. In this work, a sacrificial gallium oxide process has been proposed in which the damaged surface after ohmic annealing was oxidized by oxygen plasma treatment and thereafter etched back using HCl. As a result, the leakage current was dramatically reduced and thus the subthreshold slope was significantly improved. In addition, the maximum drain current level was increased from 594 to 634 mA/mm. To verify the effects, the surface conditions were carefully investigated using X-ray photoelectron spectroscopy.
Keywords
GaN; HFET; oxygen plasma; sacrificial oxide; X-ray photoelectron spectroscopy;
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