チョクラルスキー法によるSi単結晶育成中の点欠陥と空洞欠陥の形成エネルギに関する第一原理解析 : ドーパント型および濃度依存性

概要

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The effect of p-type (B) or n-type (P or As) dopant concentration on the formation energy E_F of point defects in Si crystals during cooling process of Czochralski method was studied with first principles analysis. E_F of several charge states of vacancy (V) and interstitial Si (I) was calculated as a function of Fermi level. By considering the dependence of Fermi level on crystal temperature, E_F of the most stable state of V and I in Si crystals was estimated. It was found that V concentration decreases in p-type while increases in n-type Si crystals when dopant concentration is higher than about 1×10^<19> atom/cm^3. This result well explains the reported experimental results for void formation behavior in Si crystals, i.e., void formation is suppressed by increase in p-type dopant concentration higher than about 1×10^<19> atom/cm^3, while void formation is enhanced by increase in n-type dopant concentration to about 3×10^<19> atom/cm^3. The other calculations showed that, at an initial stage of void formation, the reduction of the total energy of stable P-V_n or As-V_n complex formation was larger than that of stable V_n complex formation from an isolated P or As atom vacancies.
社団法人日本機械学会の論文
2006-05-25