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

Si/Ge 1-x/Si异质结双极晶体管（HBT）是用于制造Si基超快VLSI和ULSI电路的最有前途的器件之一。 用于晶体管基极的GexSi 1-x层可以通过稍微修改Si技术并利用Ge和Si的完全可结晶性来生长，以定制能隙的轮廓以获得最佳性能。 本论文的主要工作是研究生长在硅衬底上的复合GexSi_（1-x）应变薄膜的基本电学性质。 要研究的性质是主要对Si/GexSi 1-x/Si HBT的性能重要的输运参数，但也可用于其他应用。 这些包括少数载流子迁移率（或扩散率）和寿命，能隙，GexSi 1-x结。调查将作为生长条件的函数，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。 预计所提出的研究将显着提高目前的理解的Si/GexSi 1-x异质结构的体和界面特性，并将允许优化的设备，以达到更高的性能无法达到使用目前的经验方法。

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.