Imaging of threading dislocations by hyper-Raman scattering

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K22043
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 26:Materials engineering and related fields
• Research Institution: Osaka University
• Principal Investigator: Tanikawa Tomoyuki 大阪大学, 工学研究科, 准教授 (90633537)
• Project Period (FY): 2019-06-28 – 2021-03-31
• Keywords: 窒化物半導体 / 多光子顕微鏡 / 転位 / ラマン散乱

Outline of Final Research Achievements

Analysis of crystalline defects via nonlinear excitation process has been studied. First, identification of Burgers vector of threading dislocations in GaN using via multiphoton-excitation photoluminescence measurement was studied. Threading dislocations were observed as dark lines. They are classified by five according to their propagation habit and contrast. Next, edge component of threading dislocations were characterized using Raman spectroscopy. Peak wavenumber of E2-high mode was influenced by strain field by edge component of dislocations. Therefore threading edge and mixed dislocations were visualized by both multiphoton excitation photoluminescence and E2-high Raman mapping. Threading screw dislocations were only visualized by multiphoton excitation photoluminescence. Comparative study between multiphoton excitation photoluminescence and Raman spectroscopy could identify the type of dislocations.

Free Research Field

結晶工学

Academic Significance and Societal Importance of the Research Achievements

結晶欠陥の非破壊評価手法は次世代半導体の高品質化の開発だけでなく、デバイスの信頼性評価においても重要な役割を持つ。多光子励起過程を用いた結晶評価技術は、試料を加工することなく内部の欠陥を評価できることから、評価後の試料をデバイスプロセス等に利用することができ、スループットの向上や解析に係る時間の短縮につながる技術である。本研究で得られた成果を基に非破壊で結晶欠陥の識別や分類ができることで、キラー欠陥の特定につながることを期待している。