Reduction of transient enhanced diffusion in Si by F co-implantation

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K06397
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Electron device/Electronic equipment
• Research Institution: Keio University
• Principal Investigator: Uematsu Masashi 慶應義塾大学, 理工学研究科(矢上), 特任教授 (60393758)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: シリコン / 不純物 / 拡散 / ホウ素 / フッ素 / イオン注入 / 同位体 / シミュレーション

Outline of Final Research Achievements

Silicon (Si) self-diffusion and co-implanted boron (B) and fluorine (F) diffusion were simultaneously observed in pre-amorphized Si. Si self-diffusion was enhanced by F implantation, while B diffusion was reduced. This result suggests that the reduction of B diffusion by the presence of F is attributed to the I undersaturation induced by F-vacancy (V) clusters. In addition, a presence of direct interaction between F and B was also suggested. Moreover, the time dependence of F profiles indicates Ostwald ripening of FV clusters. We develop a diffusion model that takes into account FV clusters to emit V, B-F direct interaction, and two types of FV clusters for Ostwald ripening. The diffusion simulation based on this model can predict the reduced B diffusion by F in a wide range of experimental conditions.

Free Research Field

電子材料物性

Academic Significance and Societal Importance of the Research Achievements

微細化が進むシリコン半導体プロセスで、極浅接合形成における拡散制御は極めて重要な課題である。ホウ素ドーピングに広く用いられるイオン注入では、フッ素の存在がイオン注入誘起損傷によって生じるホウ素の過渡的増速拡散を抑制することが知られている。しかし、その抑制機構の詳細は明らかではなかった。本研究成果により、フッ素によるホウ素抑制機構が明らかとなり、拡散を統一的に予測するシミュレーションが可能となった。