[13p-1D-1~26] 15.4 III-V-group nitride crystals

▲ [13p-1D-9] Evaluation of dislocations in HVPE GaN single crystal by KOH etching with Na₂O₂ additive and cathodoluminescence mapping

〇Yongzhao Yao¹, Yukari Ishikawa^1,2, Yoshihiro Sugawara¹, Daisaku Yokoe¹, Masaki Sudo², Narihito Okada³, Kazuyuki Tadatomo³ (1.JFCC, 2.Nagoya Inst. of Tech, 3.Yamaguchi Univ.)

Keywords:GaN,etch pit method,dislocation

Threading dislocations (TDs) are believed to be one of the major causes of low carrier mobility, large leak current and premature breakdown in GaN power devices. TDs in GaN single crystal can generally be categorized into edge (ED, Burgers vector b=a), screw (SD, b=nc) and mixed (MD, b=nc+ma) types, and they degrade device performance differently. Therefore, revealing TDs and identifying their types are crucial to crystal growth control and failure analysis of GaN devices. In this study, we report a novel chemical etching technique using molten KOH with Na₂O₂ additive (referred to as “KN etching” henceforth), by which characteristic etch pits can be formed to identify TDs. The results are then compared with cathodoluminescence (CL) mapping.