Understanding of SEM secondary electron voltage contrast and development of quantification method

2022 Fiscal Year Final Research Report

• Project/Area Number: 18K04246
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 21050:Electric and electronic materials-related
• Research Institution: Chubu University
• Principal Investigator: Tanaka Shigeyasu 中部大学, 生命健康科学部, 教授 (70217032)
• Project Period (FY): 2018-04-01 – 2023-03-31
• Keywords: 走査型電子顕微鏡 / p-n接合 / シリコン

Outline of Final Research Achievements

To investigate the mechanism of the difference of secondary electron signal intensity between p- and n-type semiconductors in the SEM image, Monte Carlo simulations were performed under various conditions using silicon as a sample. It was found that electron scattering at the potential barrier is a key to determine the contrast. But, it takes a long time to get the results. So, with an aim of having a quick comparison between the calculated and the experimental results, the analytical formula was used for the energy distribution of the secondary electrons. This formula treats the scattering of electron wave at potential barrier quantum mechanically. The calculation was based on the patch-field model, and the contrasts calculated from the analytical formula were found to be consistent with the experiments of Si and GaN p-n junctions.

Free Research Field

電子顕微鏡学

Academic Significance and Societal Importance of the Research Achievements

半導体デバイス開発の分野では微細化の速度が非常に速く進んでいるが、加工技術のカウンターパートとなる評価技術は進展速度がやや遅れている。その一つにポテンシャル分布の解析がある。SEMは表面ポテンシャルを反映した像が得られるとされるが、その根拠は明確にされていなかった。本研究ではシミュレーションを駆使して半導体p-n接合のSEM電位コントラストの原理を解明し、コントラストとポテンシャルの間の関係を定量的に示した。