应变Si_(1-x)Ge_x层中p型杂质电离常温和低温特性  

THE MINORITY CARRIER CONCERTRATION OF STRAINED Si_(1-x)Ge_x LAYERS AS A FUNCTION OF Ge FRACTION TEMPERATURE AND IMPURITY CONCENTRATION

作　　者：赵传阵[1] 唐吉玉[1] 文于华[1] 吴靓臻[1] 孔蕴婷[1] 

机构地区：[1]华南师范大学物理与电信工程学院,广州510006

出　　处：《低温物理学报》2007年第1期57-60,共4页Low Temperature Physical Letters

摘　　要：本文采用解析的方法计算了应变Si1-xGex层中p型杂质电离度与Ge组分x、温度T以及掺杂浓度N的关系.发现常温时,在同一Ge组分下,随着掺杂浓度的升高,杂质的电离度的先变小,而后又迅速上升到1.在同一掺杂浓度下,轻掺杂时,杂质的电离度随Ge组分的增加先变大,而后几乎不变;重掺杂时,杂质电离能变为0后,杂质电离度为1.低温下,轻掺杂时,载流子低温冻析效应较为明显,杂质的电离度普遍较小,当掺杂浓度大于Mott转换点时,载流子冻析效应不再明显,电离率迅速上升到1.在同一Ge组分下,随着掺杂浓度的升高,杂质的电离度先变小,后变大,而后又迅速上升到1.在同一掺杂浓度下,轻掺杂时,杂质的电离度随Ge组分的增加变大;重掺杂时,杂质电离能变为0后,杂质电离度为1.The ratio of hole concentration to impurity concentration is calculated analytically with the varing of the temperature T, Ge fraction x and doping concentration. It is found that with the given Ge fraction, the ratio of hole concentration to impurity concentration decreases at first, and then increased sharply to 1 with the increasing of doping concentration. With the given doping concentration, the ratio of hole concentration to impurity concentration increases more and more slowly with the increasing of doping Ge fraction x at 300 K. At low temperature, freeze-out is in evidence. The ratio of hole concentration to impurity concentration is very small. When the doping concentration is large than Mott doping concentration, the atio of hole concentration to impurity concentration increases to 1. With the given Ge fraction, the the ratio of hole concentration to impurity concentration first decreases and then increase quickly to 1with the increasing of the doping concentration, with the given doping concentration, the ratio of hole concentration to impurity concentration increases more and more slowly with the light doping. For heavily doped SiGe layers, the ratio of hole concentration to impurity concentration is 1 when the the iionization energy of impertities is 0 eV.

关 键 词：硅锗合金 少数载流子 低温特性 掺杂浓度 

分 类 号：O511.4[理学—低温物理]