Dopant diffusion paths in polycrystalline silicon gate of three-dimensional metal-oxide-semiconductor field effect transistor investigated by atom probe tomography

2016 Fiscal Year Final Research Report

• Project/Area Number: 26289097
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Electron device/Electronic equipment
• Research Institution: Tohoku University
• Principal Investigator: Inoue Koji 東北大学, 金属材料研究所, 准教授 (50344718)
• Co-Investigator(Kenkyū-buntansha): 永井 康介 東北大学, 金属材料研究所, 教授 (10302209) ; 清水 康雄 東北大学, 金属材料研究所, 助教 (40581963)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: アトムプローブ / 粒界拡散 / ドーパント

Outline of Final Research Achievements

In order to investigate the dopant diffusion path of P and B in n- and p-types polycrystalline（poly-）-Si gates of trench-type three dimensional metal-oxide-semiconductor field-effect transistors, the annealing time dependence of the dopant distribution at 900℃ were analyzed by atom probe tomography. Remarkable differences between P and B diffusion behavior were observed. P atoms diffuse into deeper regions from the implanted region along grain boundaries in the n-type poly-Si gate. With longer annealing times, segregation of P on the grain boundaries was clearly observed. These results show that P atoms diffuse along grain boundaries much faster than through the bulk. On the other hand, in the p-type poly-Si gate, segregation of B was observed only at the initial stage of diffusion. After further annealing, the B atoms became uniformly distributed, and no clear segregation of B was observed. Therefore, B atoms diffuse not only along the grain boundary but also through the bulk.

Free Research Field

格子欠陥・ナノ構造分析