Germanium-based transistors for future high performance and low power logic applications
Germanium-based transistors for future high performance and low power logic applications
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DOI：
10.1109/iedm.2015.7409613
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发表时间：
2015-12
期刊：
影响因子：
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通讯作者：
Y. Yeo;X. Gong;M. V. van Dal;G. Vellianitis;M. Passlack
中科院分区：
文献类型：
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作者：
Y. Yeo;X. Gong;M. V. van Dal;G. Vellianitis;M. Passlack
在未来的晶体管中，高迁移率沟道材料可以取代应变硅来提高速度性能和/或降低功耗。在常见的元素和化合物半导体中，Ge具有最高的空穴迁移率，电子迁移率是Si的两倍。因此，Ge是未来CMOS的一种很有前途的沟道材料(图1)。关键挑战包括在可制造工艺中以成本效益的方式在硅上集成Ge，在提供高沟道迁移率的大规模EOTS上为n-FET和p-FET在Ge上形成高质量的栅堆叠，以及与其小禁带相关的泄漏问题。在本文中，我们讨论了近年来在推进基于Ge的晶体管技术方面的研究进展。将讨论在硅衬底上集成Ge以制造高性能器件和形成用于Ge FET(特别是n-FET)的高质量栅堆叠。我们还探索了提高Ge迁移率的机会，例如通过在Ge中掺入锡来形成Ge1-XSnX。此外，随着锡含量的增加，Ge1-XSNX的禁带宽度Eg变小，从间接带隙过渡到直接带隙，使Ge1-XSNX成为一种很有前途的隧道晶体管材料。
High mobility channel materials could replace strained Si to enhance speed performance and/or reduce power consumption in future transistors. Ge has the highest hole mobility among common elemental and compound semiconductors, and an electron mobility that is two times larger than that of Si. Ge is thus a promising channel material for future CMOS (Fig. 1). Key challenges include cost-effective integration of Ge on Si in a manufacturable process, formation of high-quality gate stack on Ge for n- and p-FETs at aggressively scaled EOTs that deliver high channel mobilities, and leakage issues related to its small bandgap. In this paper, we discuss recent research progress in advancing Ge-based transistor technologies. Integration of Ge on Si substrate to enable fabrication of high performance devices and formation of high-quality gate stack for Ge FETs (particularly for n-FETs) will be discussed. We also explore opportunities to boost the mobility of Ge, e.g. by incorporating Sn in Ge to form Ge1-xSnx. Furthermore, by raising the Sn composition, the band gap EG of Ge1-xSnx becomes smaller and transits from indirect to direct, making Ge1-xSnx a promising material for tunneling transistors.