Predoping effects of boron and phosphorous on arsenic diffusion along grain boundaries in polycrystalline silicon investigated by atom probe tomography

3次元アトムプローブによる多結晶シリコン中のヒ素の粒界拡散に対するリンまたはホウ素添加効果の分析

高見澤 悠 ; 清水 康雄*; 井上 耕治*; 野沢 康子*; 外山 健*; 矢野 史子*; 井上 真雄*; 西田 彰男*; 永井 康介*

Takamizawa, Hisashi; Shimizu, Yasuo*; Inoue, Koji*; Nozawa, Yasuko*; Toyama, Takeshi*; Yano, Fumiko*; Inoue, Masao*; Nishida, Akio*; Nagai, Yasuyoshi*

The effect of phosphorus (P) and boron (B) doping on arsenic (As) diffusion in polycrystalline silicon (poly-Si) was investigated using laser-assisted atom probe tomography. In all samples, a high concentration of As was found at the grain boundaries, indicating that such boundaries represent the main diffusion path. However, As grain-boundary diffusion was suppressed in the B-doped sample, and enhanced in the P-doped sample. In a sample co-doped with both P and B, As diffusion was somewhat enhanced, indicating competition between the effects of the two dopants. This can be explained by the pairing of P and B atoms. The results suggest that grain-boundary diffusion of As can be controlled by varying the local concentration of P and B dopants.