Effects of dielectric loss mechanisms at electron trapping sites on damage recovery and reliability improvement in thin films

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K18875
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 28:Nano/micro science and related fields
• Research Institution: Kyoto University
• Principal Investigator: Eriguchi Koji 京都大学, 工学研究科, 教授 (70419448)
• Project Period (FY): 2021-07-09 – 2023-03-31
• Keywords: 欠陥 / マイクロ波照射 / シリコン窒化膜 / 電気容量

Outline of Final Research Achievements

This study focuses on dielectric loss mechanisms by microwave annealing (MWA) that leads to the reconstruction of defect structures in thin films. Silicon nitride (SiN) films were prepared on Si substrates and exposed to low pressure/low temperature plasmas for defect creation. A few-nm thick damaged region was formed. Plasma-exposed samples were treated with an MWA. The changes of defect structures were investigated in detail using electrical characterization techniques. The shift of flat-band voltage in the positive direction were clarified after the MWA. These findings imply that the MWA induces the reconstruction of carrier trapping sites (localized defect structures).

Free Research Field

ナノ材料信頼性物理学

Academic Significance and Societal Importance of the Research Achievements

電子デバイスに用いられる機能材料中に形成される欠陥構造は，電子捕獲型準位に代表される設計外の局所電子構造である．本研究では，窒化シリコン膜（SiN）を主な対象とし，従来の高温熱処理に代わる電磁波（マイクロ波）照射による低温非平衡プロセス（MWA）による欠陥構造回復機構の解明を試みた．その結果，欠陥構造がMWAにより変調されること，すなわち欠陥構造が修復される可能性があることが明らかになった．この事実は，MWAが高温プロセスに適さない材料含め様々な材料が搭載される機能素子の超高度信頼性技術開発に寄与することを示す重要な知見である．