Determination of formation energy of single vacancy in silicon by means of rapir queching of high-temperature thermal euilibrium

2017 Fiscal Year Final Research Report

• Project/Area Number: 26390055
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Crystal engineering
• Research Institution: Kyushu Institute of Technology
• Principal Investigator: Kaneta Hiroshi 九州工業大学, 大学院生命体工学研究科, 特任教授 (30418131)
• Co-Investigator(Renkei-kenkyūsha): NEMOTO Yuichi 新潟大学, 自然科学系, 准教授 (10303174) ; GOTO Terutaka 新潟大学, フェロー (60134053)
• Project Period (FY): 2014-04-01 – 2018-03-31
• Keywords: シリコン / 原子空孔 / 形成エネルギー

Outline of Final Research Achievements

The silicon wafers were annealed at high-temperatures, to successfully realize the thermal equilibrium of defects in the silicon wafers. The wafers were then quenched. The concentrations of the quenched-in vacancies were determined by means of the low-temperature ultrasonic measurement for the softening of the elastic constant C44. By applying our theory of low-temperature elastic softening to the measured softening, we determined the concentration of quenched-in vacancies. Using these values, we evaluated the formation energy of the vacancy. The obtained value for the formation energy was smaller than expected from the conventional knowledge. We however clarified the reason for the disagreement: imperfect quenching with insufficient cooling rate and neglect of the out-diffusion of the vacancies. We conclude that our experimental approach will allow us to derive the accurate value of the vacancy’s formation energy, if these inappropriate procedures in the experiment will be corrected.

Free Research Field

半導体材料科学