不同直径张应变锗材料对光谱和晶体质量的影响

绝缘体上张应变锗材料是通过能带工程提高锗材料光电性能得到的一种新型半导体材料,在微电子和光电子领域具有重要的应用前景.采用微电子技术中的图形加工方法以及利用锗浓缩的技术原理,在绝缘体上硅(SOI)材料上制备了绝缘体上张应变锗材料.喇曼与室温光致发光(PL)测试结果表明,不同圆形半径的绝缘体上锗材料张应变均为0.54％.对于绝缘体上张应变锗材料,应变使其发光红移的效果强于量子阱使其发生蓝移的效果,总体将使绝缘体上张应变锗材料的直接带发光峰位红移.同时0.54％张应变锗材料的直接带发光强度随着圆形半径的增大而减弱,这主要是因为圆形半径大的样品其晶体质量较差.该材料可进一步用于制备锗微电子和光电子器件.     

Properties of n-Ge epilayer on Si substrate with in-situ doping technology

The properties of n-Ge epilayer deposited on Si substrate with in-situ doping technology in a cold-wall ultrahigh vacuum chemical vapor deposition(UHVCVD) system are investigated.The growth temperature of ~500℃ is optimal for the n-Ge growth in our equipment with a phosphorus concentration of ~10~(18)cm~(-3).In the n-Ge epilayer,the depth profile of phosphorus concentration is box-shaped and the tensile strain of 0.12% confirmed by x-ray diffraction measurement is introduced which results in the red shift of the photoluminescence.The enhancements of photoluminescence intensity with the increase of the doping concentration are observed,which is consistent with the modeling of the spontaneous emission spectrum for direct transition of Ge.The results are of significance for guiding the growth of n-Ge epilayer with in-situ doping technology.