Development of AlN Wavelength Conversion Devices Using Vertical Polarity Inversion

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K15045
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 21060:Electron device and electronic equipment-related
• Research Institution: Osaka University
• Principal Investigator: Hayashi Yusuke 大阪大学, 基礎工学研究科, 助教 (00800484)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: AlN / 極性反転

Outline of Final Research Achievements

This project aims to elucidate the physics of polarity inversion in AlN and its application to wavelength conversion devices utilizing vertically polarity-inverted AlN structure. Polarity inversion structures in face-to-face annealed sputter-deposited AlN (FFA Sp-AlN) were analyzed by HAADF-STEM and EELS for the first time, clarifying that the oxygen concentration distribution is strongly correlated with the polarity inversion. Furthermore, we discovered novel methods to control the polarity inversion structure by modulating the oxygen concentration utilizing oxygen plasma irradiation and surface cleaning. This study provides essential insights into the precise control of polarity, which is the core of vertical polarity inversion devices.

Free Research Field

結晶成長

Academic Significance and Societal Importance of the Research Achievements

本研究で得られた極性反転構造の観察方法、発生メカニズム、制御方法は、垂直極性反転デバイスの極性・膜厚を精密に制御するうえで重要な知見となる。特に、酸素プラズマ照射や表面クリーニングによりAlN表面の酸素濃度を変調することで極性反転構造を制御する手法は本研究を通じて新たに発見された。さらに、多層弾性膜における熱歪解析手法を開発したことで、導波路デバイスの作製ウィンドウの見積もりと光弾性効果の解析を容易に実現できるようになった。以上の結果により、小型かつ高効率な深紫外コヒーレント光源に向けた要素技術の開発に成功した。