Mechanism of dopant segregation to SiO 2 / Si ( 001 ) interfaces
Mechanism of dopant segregation to SiO 2 / Si ( 001 ) interfaces
复制标题
SiO 2 / Si ( 001 ) 界面掺杂剂偏析机制
DOI：
10.1103/physrevb.65.245305
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发表时间：
2002
影响因子：
3.7
通讯作者：
M. Caldas
中科院分区：
文献类型：
--
作者：
J. Dabrowski;H. Müssig;V. Zavodinsky;R. J. Baierle;M. Caldas
Dopant atoms can segregate to ${\mathrm{SiO}}_{2}/\mathrm{Si}(001)$ interfaces and be deactivated there. Using phosphorus as a typical example of a donor and guided by results of ab initio calculations, we present a model of donor segregation. We find that P is trapped at the interface in the form of threefold-coordinated atoms. The atomic detailed configuration and the process of P incorporation depend on P concentration ${C}_{\mathrm{P}}$ in the vicinity of the interface. At low ${C}_{\mathrm{P}},$ phosphorus atoms prefer to substitute Si atoms with dangling bonds. At high ${C}_{\mathrm{P}},$ phosphorus pairs are formed. At intermediate ${C}_{\mathrm{P}},$ (around ${10}^{17}\char21{}{10}^{19} {\mathrm{cm}}^{\ensuremath{-}3})$ segregation occurs to sites associated with interface roughness and to interface Si-Si bridges, and is mediated by diffusion and annihilation of Si dangling bonds and by reoxidation during oxide annealing. Making diffusion of dangling bonds more difficult (for example, by nitridation) should, therefore, reduce the trapping efficiency of ${\mathrm{SiO}}_{2}/\mathrm{Si}(001)$ in the technologically important regime of intermediate ${C}_{\mathrm{P}}.$
Dopant atoms can segregate to ${\mathrm{SiO}}_{2}/\mathrm{Si}(001)$ interfaces and be deactivated there. Using phosphorus as a typical example of a donor and guided by results of ab initio calculations, we present a model of donor segregation. We find that P is trapped at the interface in the form of threefold-coordinated atoms. The atomic detailed configuration and the process of P incorporation depend on P concentration ${C}_{\mathrm{P}}$ in the vicinity of the interface. At low ${C}_{\mathrm{P}},$ phosphorus atoms prefer to substitute Si atoms with dangling bonds. At high ${C}_{\mathrm{P}},$ phosphorus pairs are formed. At intermediate ${C}_{\mathrm{P}},$ (around ${10}^{17}\char21{}{10}^{19} {\mathrm{cm}}^{\ensuremath{-}3})$ segregation occurs to sites associated with interface roughness and to interface Si-Si bridges, and is mediated by diffusion and annihilation of Si dangling bonds and by reoxidation during oxide annealing. Making diffusion of dangling bonds more difficult (for example, by nitridation) should, therefore, reduce the trapping efficiency of ${\mathrm{SiO}}_{2}/\mathrm{Si}(001)$ in the technologically important regime of intermediate ${C}_{\mathrm{P}}.$