Buried Ge-Si-C Channels and Applications

这个项目将探索锗-硅-碳应变层沟道的生长及其在半导体器件中的应用。锗硅应变外延层一直是研究的热点，最近已被应用于异质结双极晶体管。此外，锗-硅层还被用于制作异质结场效应晶体管，这可能会为CMOS场效应晶体管提供更高性能的p沟道晶体管。在这两种情况下，可获得的性能改善都受到在后续工艺中可以在保持完全应变的层的同时掺入的锗的量的限制。均匀的锗-硅-碳外延层将通过UHV/CVD生长并应用于新的器件结构。将制作一种埋沟电荷耦合器件，其工作温度比现有的电荷耦合器件更低。这种电荷耦合器件在天文成像方面具有潜在的应用前景。此外，它还将有助于研究锗-硅-碳外延层中的输运，从而加深对异质场效应晶体管的理解。该项目的一个关键部分是低碳浓度(=0.2%)的外延层的生长，该外延层的热稳定性得到了改善，该项目还将探索非均匀沟道的生长和应用。当在适当的条件下生长时，会形成波纹层，并在高波幅的极限下形成孤岛(或量子点)。量子点阵列可用于执行量子细胞自动机(QCA)概念中的逻辑功能。在QCA逻辑的一种实现中，必须选通量子点之间的传输。在锗-硅-碳系统中生长出大小和间距合适的量子点，用于探索量子点之间的门控输运。这一项目将产生对硅集成电路技术有利的结果，也将对更具异国情调和投机性的器件产生好处。研究均匀的Ge-Si-C沟道将改善异质结场效应晶体管在CMOS中的应用前景，并将有助于更好地理解限制载流子迁移率的因素。研究量子点之间的门控传输将改善基于量子细胞自动机的高级计算的前景。*

9821054GreveThis project will explore the growth and applications of germanium-silicon-carbon strained-layer channels in semiconductor devices. Germanium-silicon strained epitaxial layers have been the subject of intense research and have recently been applied to heterojunction bipolar transistors. In addition, germanium-silicon layers have been used to fabricate heterostructure field effect transistors which might provide higher performance p-channel transistors for CMOS. In both cases, the attainable performance improvement has been limited by the amount of germanium which can be incorporated while maintaining fully strained layers during subsequent processing.Uniform germanium-silicon-carbon epitaxial layers will be grown by UHV/CVD and applied to novel device structures. A buried-channel charge-coupled device (CCD) will be fabricated which can operate at lower temperatures than existing CCDS. Such a CCD is potentially applicable to astronomical imaging. In addition, it will facilitate studies of the transport in germanium-siliconcarbon epitaxial layers which will lead to improved understanding of heterostructure field effect transistors. A crucial part of this project is the growth of epitaxial layers with low carbon concentration (=O.2 %) which nevertheless have improved thermal stability,This project will also explore the growth and application of nonuniform channels. When grown under the proper conditions undulated layers are formed and in the limit of high undulation amplitude isolated islands (or quantum dots) are formed. Arrays of quantum dots can be used to perform logic functions in the quantum cellular automata (QCA) concept. In one implementation of QCA logic, it is necessary to gate transport between the quantum dots. Quantum dots with the appropriate size and spacing will be grown in the germanium-silicon-carbon system, which will then be used to explore gated transport between quantum dots.This project will yield results of benefit to both silicon integrated circuit technology and also to more exotic and speculative devices. Work on uniform germanium-silicon-carbon channels will improve the prospects for the use of heterostructure field effect transistors in CMOS and will also lead to improved understanding of the factors which limit carrier mobility. Studies of gated transport between quantum dots will improve the prospects for advanced quantum cellular automata-based computing.***