[13p-N101-1~18] 15.4 III-V-group nitride crystals

[13p-N101-1] High-Resolution Mass Spectrometry Analysis of the Reactions Between Trimethylgallium and Ammonia in GaN MOVPE Using Hydrogen Isotope Labeling

〇Zheng Ye¹, Shugo Nitta¹, Yoshio Honda^1,2, Markus Pristovsek¹, Hiroshi Amano^1,3,4 (1.IMaSS, Nagoya Univ., 2.IAR, Nagoya Univ., 3.ARC, Nagoya Univ., 4.VBL, Nagoya Univ.)

Keywords:Gas phase reaction, carbon

Based on the requirements of high breakdown voltage vertical GaN-based power devices, reducing unintentional carbon (C) incorporation in the thick drift layers is required. Metalorganic vapor phase epitaxy (MOVPE) is a common crystal growth method of GaN devices. Since the direct source of C is the trimethylgallium (Ga(CH₃)₃, TMGa) precursor, an in-depth understanding of the growth process of GaN in MOVPE is necessary. Recently, we employed a time-of-flight mass spectrometry (TOF-MS) for vapor phase reaction analysis of GaN growth. H₂ promotes the decomposition of Ga(CH₃)₃, but how the precursors reacts to each other in the Ga(CH₃)₃/NH₃/H₂ system is not clear. In order to further understanding the mechanisms of GaN growth, we used D₂ (Deuterium, H₂ isotope) as a carrier gas to trace the specific reaction process of Ga(CH₃)₃ and NH₃ in this study. As a result, it is shown that Ga(CH₃)₃ reacts preferentially with NH₃ instead of D₂. NH₃ plays a dominant role in Ga(CH₃)₃ decomposition process, which leads to suppression of the C incorporation in GaN growth at a high V/III ratio.