Control of Polarization-Induced Electric Field in Nitride-Semiconductor-Based Devices

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K18074
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Electronic materials/Electric materials
• Research Institution: Tohoku University
• Principal Investigator: Tanikawa Tomoyuki 東北大学, 金属材料研究所, 講師 (90633537)
• Research Collaborator: MATSUOKA takashi
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 変調分光 / 窒化物半導体 / 分極電界 / 有機金属気相成長

Outline of Final Research Achievements

InGaN-based light-emitting diodes on GaN films with various crystal orientation were fabricated, and internal electric fields were evaluated using a electroreflectance method. Electroreflectance signals were originated from internal electric fields applied in GaN barrier and InGaN well layers. From the signal phase and the signal period, direction and intensity of electric fields could experimentally be measured.
N-polar InGaN/AlGaN/GaN-based heterostructure field-effect transistors were fabricated and concentration of two-dimensonal electron gas was investigated. first, GaN/AlGaN/GaN structures were fabricated and alloy composition and thickness of AlGaN were optimized. Two dimensional electron gas in N-polar GaN/AlGaN/GaN had a high density of two-dimensional electron gas with 1E13 cm-2. InGaN channel could enhance the electron density. When InN alloy composition of was 0.11, electron concentration was twice.

Free Research Field

結晶工学

Academic Significance and Societal Importance of the Research Achievements

窒化物半導体などの次世代半導体材料は強い分極を有し、誘電体的性質がデバイス性能を左右する。このような観点でデバイス開発を俯瞰すると、分極効果を定量評価する技術が必要といえる。本研究ではInGaN/GaN発光ダイオードとGaN/AlGaN/GaNヘテロ接合電界効果トランジスタを例として、デバイス動作時の電界強度を定量評価する技術と分極効果を制御する技術について研究を展開した。その結果、分極電界の定量評価に変調分光法が有用であることを示し、混晶などの分極不連続量の制御により電子の偏りを制御できることを示した。これらの成果は、発光デバイスや電子デバイスの性能改善に向けて役立つ知見といえる。