1. Degradation of 2DEG transport properties in GaN-capped AlGaN/GaN heterostructures at 600 °C in oxidizing and inert environments
- Author
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Ateeq J. Suria, Xiaoqing Xu, Sambhav R. Jain, Thomas A. Heuser, Hongyun So, Debbie G. Senesky, and Minmin Hou
- Subjects
010302 applied physics ,Auger electron spectroscopy ,Electron mobility ,Materials science ,Argon ,Photoluminescence ,Passivation ,Annealing (metallurgy) ,Analytical chemistry ,General Physics and Astronomy ,chemistry.chemical_element ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Van der Pauw method ,chemistry ,Hall effect ,0103 physical sciences ,0210 nano-technology - Abstract
In this paper, the electron mobility and sheet density of the two-dimensional electron gas (2DEG) in both air and argon environments at 600 °C were measured intermittently over a 5 h duration using unpassivated and Al2O3-passivated AlGaN/GaN (with 3 nm GaN cap) van der Pauw test structures. The unpassivated AlGaN/GaN heterostructures annealed in air showed the smallest decrease (∼8%) in 2DEG electron mobility while Al2O3-passivated samples annealed in argon displayed the largest drop (∼70%) based on the Hall measurements. Photoluminescence and atomic force microscopy showed that minimal strain relaxation and surface roughness changes have occurred in the unpassivated samples annealed in air, while those with Al2O3 passivation annealed in argon showed significant microstructural degradations. This suggests that cracks developed in the samples annealed in air were healed by oxidation reactions. To further confirm this, Auger electron spectroscopy was conducted on the unpassivated samples after the anneal in...
- Published
- 2017