Kim Yong-Sung, Lee Eun-Cheol, Chang K J
Department of Physics, Korea Advanced Institute of Science and Technology, Daejon 305-701, Korea.
Phys Rev Lett. 2003 Sep 19;91(12):125503. doi: 10.1103/PhysRevLett.91.125503. Epub 2003 Sep 18.
Based on first-principles density-functional calculations, we propose a class of nearest-neighbor donor pairs that are energetically favorable in highly n-type Si. These donor pairs comprise dopant atoms either fourfold coordinated at the nearest-neighbor distance or threefold coordinated through bond-breaking relaxations. For P and As dopants, the two defect states are very close in energy, less than 0.1 eV, while the threefold coordinated state is more stable by 0.24 eV for Sb dopants. The former state has a very deep donor level close to the valence band maximum, while the defect level lies deep inside the valence band for the latter. Thus, both the donor pairs are electrically inactive at very high doping levels, and they are suggested to be responsible for the observed saturation of carriers.
基于第一性原理密度泛函计算，我们提出了一类在高n型硅中能量上有利的最近邻施主对。这些施主对由在最近邻距离处四重配位的掺杂原子或通过键断裂弛豫三重配位的掺杂原子组成。对于P和As掺杂剂，两种缺陷态的能量非常接近，小于0.1 eV，而对于Sb掺杂剂，三重配位态更稳定0.24 eV。前一种态具有非常深的施主能级，接近价带最大值，而后一种态的缺陷能级位于价带深处。因此，这两种施主对在非常高的掺杂水平下都是电惰性的，并且它们被认为是导致观察到的载流子饱和的原因。
