サトウ　ノブオ   Satoh Nobuo   佐藤　宣夫    所属   千葉工業大学  工学部 機械電子創成工学科    千葉工業大学  工学研究科 工学専攻    千葉工業大学  工学研究科 機械電子創成工学専攻    職種   教授
言語種別	英語
発行・発表の年月	2017/07
形態種別	学術雑誌
標題	Evaluation of carrier concentration reduction in GaN-on-GaN wafers by Raman spectroscopy and Kelvin force microscopy
執筆形態	共著
掲載誌名	Japanese Journal of Applied Physics
巻・号・頁	Volume 56(Number 8S1)
著者・共著者	Hidekazu Yamamoto, Kazuya Agui, Yuhki Uchida, Shota Mochizuki, Takeshi Uruma, Nobuo Satoh and Tamotsu Hashizume
概要	The carrier concentration in a gallium nitride (GaN) substrate of a GaN-on-GaN wafer grown by hydride vapor phase epitaxy (HVPE) was evaluated by Raman spectroscopy and Kelvin probe force microscopy (KFM). On the basis of the longitudinal optical phonon-plasmon coupled (LOPC) mode of Raman spectra and surface potential measurements by KFM, the carrier concentration at the periphery of the HVPE-GaN substrate was found to be about one order of magnitude lower than that at the center. The decrease in carrier concentration is considered to be due to the out-diffusion of dopants during the metal organic chemical vapor deposition (MOCVD) of the epitaxial layer. In silicon (Si) epitaxial wafers, the autodoping of out-diffused dopants introduces nonuniform device characteristics. This undesirable effect needs to be suppressed to successfully move from prototype GaN-on-GaN power devices to commercial products.
DOI	10.7567/JJAP.56.08LB07