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http://dx.doi.org/10.6111/JKCGCT.2014.24.5.196

Investigation of defects and surface polarity in AlN and GaN using wet chemical etching technique  

Hong, Yoon Pyo (Division of Materials Science and Engineering, Hanyang University)
Park, Jae Hwa (Division of Materials Science and Engineering, Hanyang University)
Park, Cheol Woo (Division of Materials Science and Engineering, Hanyang University)
Kim, Hyun Mi (Division of Materials Science and Engineering, Hanyang University)
Oh, Dong Keun (Division of Materials Science and Engineering, Hanyang University)
Choi, Bong Geun (Division of Materials Science and Engineering, Hanyang University)
Lee, Seong Kuk (Unimo Photron Co., Ltd.)
Shim, Kwang Bo (Division of Materials Science and Engineering, Hanyang University)
Publication Information
Journal of the Korean Crystal Growth and Crystal Technology / v.24, no.5, 2014 , pp. 196-201 More about this Journal
Abstract
We investigated defects and surface polarity in AlN and GaN by using wet chemical etching. Therefore, the effectiveness and reliability of estimating the single crystals by defect selective etching in NaOH/KOH eutectic alloy have been successfully demonstrated. High-quality AlN and GaN single crystals were etched in molten NaOH/KOH eutectic alloy. The etching characteristics and surface morphologies were carried out by scanning electron microscope (SEM) and atomic force microscope (AFM). The etch rates of AlN and GaN surface were calculated by etching depth as a function of etching time. As a result, two-types of etch pits with different sizes were revealed on AlN and GaN surface, respectively. Etching produced hexagonal pits on the metal-face (Al, Ga) (0001) plane, while hexagonal hillocks formed on the N-face. On etching rate calibration, it was found that N-face had approximately 109 and 15 times higher etch rate than the metal-face of AlN and GaN, respectively. The size of etch pits increased with an increase of the etching time and they tend to merge together with a neighbouring etch pits. Also, the chemical mechanism of each etching process was discussed. It was found that hydroxide ion ($OH^-$) and the dangling bond of nitrogen play an important role in the selective etching of the metal-face and N-face.
Keywords
KOH/NaOH; Etching; AlN; GaN; Wet etching; Etch pit; Etch rate;
Citations & Related Records
Times Cited By KSCI : 2  (Citation Analysis)
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