CALCULATION OF THE BANDGAP NARROWING DUE TO HEAVY DOPING IN p-TYPE STRAINED Si1-xGex LAYERS
Wu Wengang①; Zhang Wanrong②; Jiang Desheng①; Luo Jinsheng②
①National Lab. for Supperlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences; Beijing 100083;②Department of Electronic Engineering,Xi'an Jiaotong University, Xi'an 710049
Abstract：To take the effects of strain induced splitting and non-parabolicity of valence band into account when calculating the bandgap narrowing (BGN) due to heavy doping in p-type pseu-domorphic Si1-xGex layers grown on < 100 > Si substrate, an equivalent effective degeneracy (EED) model is proposed for the valence band structure of the strained alloy. The calculation results agree very well with published experimental data and show that there is a maximum value of the BGN at a certain Ge fraction if dopant concentration exceeds about 2～3 × 1019cm-3, and that, otherwise, it will decrease continuously as Ge fraction increases.
1996, Vol. 18 
