Investigation of the Transport Properties in Thin Strained GexSil-x Layers, with Applications to Heterojunction BipolarTransistor

Si/Ge1-x/Si异质结双极晶体管（HBT）是制造基于Si的超高速VLSI和ULSI电路最有前途的器件之一。用于晶体管基底的GexSi1-x层可以通过稍微修改Si技术来生长，并利用Ge和Si的完全混溶来定制能隙的轮廓，以获得最佳性能。这项工作将集中于研究生长在硅衬底上的复合材料GexSi1-x应变薄层的基本电子特性。要研究的性质是传输参数，这对Si/GexSi1-x/Si HBT的性能至关重要，但对其他应用也很有用。这些包括少数载流子迁移率（或扩散率）和寿命，能隙，GexSi1-x结。将研究生长条件、层厚度和组成（Ge含量x）、应变和应变弛豫（通过退火）、掺杂杂质浓度和温度的函数。预计所提出的研究将大大提高目前对Si/GexSi1-x异质结构的体积和界面性质的理解，并将允许优化器件以达到使用当前经验方法无法达到的更高性能。

9220382 Neugroschel The Si/Ge1-x/Si heterojunction bipolar transistor (HBT) is one of the most promising devices for manufacturing Si-based ultrafast VLSI and ULSI circuits. The GexSi1-x layer, used for the base of the transistor, can be grown by slightly modifying the Si technology and taking advantage of the complete miscibility of Ge and Si to tailor the profiles of the energy gap for optimum performance. The proposed work will concentrate on the investigation of the fundamental electronic properties of the composite GexSi1-x strained thin layers grown on silicon substrate. The properties to be investigated are the transport parameters important primarily to the performance of the Si/GexSi1-x/Si HBT, but useful also for other applications. These include the minority-carrier mobility (or diffusivity) and lifetime, energy gap, GexSi1-x junction. The investigation will be made as a function of growth conditions, the layer thickness and compostion (Ge content x), strain and strain relaxation (via annealing), dopant impurity concentration and temperature. It is expected that the proposed research will significantly enhance the present understanding of the bulk and interface properties of the Si/GexSi1-x heterostructures, and will allow optimization of device to reach higher performance not attainable using the current empirical approach.