杂质电离现象是“半导体物理学”课程的重要知识点和难点之一.本文通过对杂质电离的深入分析，推导出杂质电离程度η、温度T、掺杂浓度ND及施主杂质电离能ΔED等4 个重要物理量之间的关系.进一步深入讨论杂质完全电离的最大掺杂浓度上限、电离比例与杂质电离能的关系，同时引入Lambert W 函数简化对温度的求解.最后研究4H-SiC 中杂质不完全电离的问题.本文的分析方法不仅可加强学生对杂质电离的系统理解，而且可培养学生的分析和创新能力，有助于将来研究和设计半导体器件.

The incomplete ionization of impurities in semiconductors is one of the key and difficult points in the course of Physics of Semiconductor. By the profound analysis on the incomplete ionization of impurities，this paper deduces the relationship among the four essential parameters of the ionization rate η，the temperature T，the doping concentration ND and the ionized energy ΔED. Furthermore，the maximum doping concentration for complete ionization as well as the dependence of the ionization rate upon the ionized energy are proposed，and the introduction of the Lambert W-function simplifies the solution of temperature. Moreover，the issue of the incomplete ionization in 4H-SiC is discussed. The discussions and conclusions are beneficial for the students to have the systematic comprehension on the basic problems concerning incomplete ionization of impurities，and to develop the ability of analysis and innovation for future research and design work in the fields of semiconductor devices.