Comparative Study of Carrier Lifetime Dependence on Dopant Concentration in Silicon and Germanium
Comparative Study of Carrier Lifetime Dependence on Dopant Concentration in Silicon and Germanium
复制标题
硅和锗中载流子寿命对掺杂剂浓度依赖性的比较研究
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
J. Vanhellemont
中科院分区：
文献类型：
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作者：
E. Gaubas;J. Vanhellemont
越来越多地使用薄锗层在硅衬底上作为有源层在先进的电子器件中的激励和掺杂剂浓度的载流子复合特性的依赖性在两个半导体的比较研究的动机。通过研究具有不同几何形状和表面处理的样品，分离了载流子寿命的体相和表面成分。体载流子寿命被确定为掺杂剂浓度的函数，并且在锗的情况下也被确定为激发能级的函数。体寿命的观察相结合的寿命根据肖克利-读取-霍尔（SRH）理论与俄歇复合以上的掺杂浓度阈值的寿命进行了模拟。结果表明，Si和Ge中的体载流子寿命行为非常相似。Si中的载流子寿命变化可以很好地描述由SRH和俄歇复合模型相结合，而Ge中的寿命变化很好地拟合SRH模型，考虑到注入水平的寿命依赖性。结果表明，锗中掺杂剂浓度的寿命依赖性可以通过假设复合中心浓度随掺杂剂浓度线性增加来唯象地描述。结果还说明了表面钝化和材料质量的重要性，这取决于制造技术，当比较不同的设备和不同的样品上获得的载流子寿命。
The increasing use of thin germanium layers on silicon substrates as active layers in advanced electronic devices is the motivation for a comparative study of the dependence of the carrier recombination characteristics on excitation and dopant concentration in both semiconductors. Bulk and surface components of the carrier lifetime are separated by studying samples with different geometries and surface finishing. The bulk carrier lifetime is determined as a function of dopant concentration and in the case of germanium also as a function of the excitation level. The bulk lifetime observations are simulated by combining the lifetime according to Shockley-Read-Hall (SRH) theory with the lifetime resulting from Auger recombination above a doping concentration threshold. It is shown that the bulk carrier lifetime behavior in Si and Ge is very similar. Carrier lifetime changes in Si can be well described by a combined SRH and Auger recombination model, while lifetime variations in Ge fit well the SRH model, taking into account the lifetime dependence on the injection level. It is shown that the lifetime dependence on dopant concentration in germanium can be phenomenologically described by assuming a linear increase of recombination center concentration with dopant concentration. The results also illustrate the importance of surface passivation and of material quality which depends on the fabrication technology, when comparing carrier lifetimes obtained with different equipment and on different samples.