As＋注入Si1—xGex的快速退火行为

Annealing Behavior of As￣+ Implant in Si_(1-x)Ge_x Epilayers by RTA

用二次离子质谱对Ａｓ＋注入Ｓｉ（１－ｘ）Ｇｅｘ的快速退火行为进行了研究．Ｓｉ（１－ｘ）Ｇｅｘ样品中Ｇｅ组分分别为ｘ＝０．０９，０．２７和０．４３．Ａｓ＋注入剂量为２×１０（１６）ｃｍ（－２），注入能量为１００ｋｅＶ．快速退火温度分别为９５０℃和１０５０℃，时间均为１８秒．实验结果表明，Ｓｉ（１－ｘ）Ｇｅｘ中Ａｓ的扩散与Ｇｅ组分密切相关，Ｇｅ组分越大，Ａｓ扩散越快．对于Ｇｅ组分较大的Ｓｉ１－ｘＧｅｘ样品，Ａｓ浓度分布呈现“盒形”（ｂｏｘ－ｓｈａｐｅｄ），表明扩散与Ａｓ浓度有关．Ｓｉ１－ｘＧｅｘ样品中Ａｓ的快扩散可能与未激活Ａｓ的快速退火行为有关．就作者所知，离子注入Ａｓ在Ｓｉ（１－ｘ）Ｇｅｘ中的扩散研究，以前未见报道．

Abstract Diffusion of ion implanted As in relaxedSi1-xGex is studied as a function of Ge content over a wide range of Ge fractions (0～43%) and annealing temperature for the first time. The samples were implanted at an energy of 100keV with a dose of 2×1016cm-2 and subsequently rapid thermally annealed (RTA) for 18 second at 950℃ and 1050℃,respectively. Arsenic concentration profiles measured by using secondary-ion-mass spectroscopy(SIMS)suggest that the behavior of implanted As in Si1-xGex after RTA is different from that in Si, and the Si1-xGex samples exhibit box-shaped, concentration-dependent diffusion profiles with increasing Ge content. Experimental results show that the arsenic diffusion is enhanced with increasing temperature for certain Ge content and strongly dependent on Ge content, and the higher Ge content, the faster As diffusion. Based on the experimental results, we have discussed the diffusion mechanism in St1-xGex alloys and reasonably explained the faster As diffusion in St1-xGex alloys compared to diffusion in Si.