Development of surface acoustic wave devices and its application to strongly correlated electron systems

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K13518
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Condensed matter physics II
• Research Institution: Niigata University
• Principal Investigator: NEMOTO Yuichi 新潟大学, 自然科学系, 准教授 (10303174)
• Co-Investigator(Renkei-kenkyūsha): AKATSU Mitsuhiro 新潟大学, 自然科学系, 助教 (10431876) ; MITSUMOTO Keisuke 新潟大学, 自然科学系, 特任助教 (50515567)
• Research Collaborator: KANETA Hiroshi 九州工業大学, 特任教授 ; GOTO Terutaka 新潟大学, 自然科学系, フェロー ; KASHIMA Kazuhiko グローバルウェーハズ・ジャパン(株), 技監
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 超音波計測 / 原子空孔 / 表面弾性波 / 半導体 / 強相関電子系

Outline of Final Research Achievements

Observation of vacancy in silicon crystal and elucidation of its electronic state is a challenging issue in both solid-state physics and application technologies. We successfully observe vacancy orbital through elastic softening with decreasing temperature by using ultrasound measurements. Extended vacancy orbital leads to extremely strong quadrupole-strain interaction, which allows us to observe elastic softening at low temperatures even in dilute vacancy below 1 ppb. Especially, evaluation of vacancy concentration in a surface region of highly qualified silicon wafers is desirable for control of micro defects, that originates in vacancy, about nanometer in size. A benchmark of the achievement of surface acoustic wave with high frequency measurements will be a powerful evaluating method in rapidly advancing semiconductor industry.

Free Research Field

物性実験