限制对 Ge-Si(x)Ge(1-x) 核壳纳米线中载流子输运的作用。

Role of confinement on carrier transport in Ge-Si(x)Ge(1-x) core-shell nanowires.

机构信息

Microelectronics Research Center, Department of Electrical and Computer Engineering, The University of Texas, Austin, Texas 78758, USA.

出版信息

Nano Lett. 2012 Jan 11;12(1):108-12. doi: 10.1021/nl2030695. Epub 2011 Dec 6.

DOI:10.1021/nl2030695

PMID:22111925

Abstract

We examine the impact of shell content and the associated hole confinement on carrier transport in Ge-Si(x)Ge(1-x) core-shell nanowires (NWs). Using NWs with different Si(x)Ge(1-x) shell compositions (x = 0.5 and 0.7), we fabricate NW field-effect transistors (FETs) with highly doped source/drain and examine their characteristics dependence on shell content. The results demonstrate a 2-fold higher mobility at room temperature, and a 3-fold higher mobility at 77K in the NW FETs with higher (x = 0.7) Si shell content by comparison to those with lower (x = 0.5) Si shell content. Moreover, the carrier mobility shows a stronger temperature dependence in Ge-Si(x)Ge(1-x) core-shell NWs with high Si content, indicating a reduced charge impurity scattering. The results establish that carrier confinement plays a key role in realizing high mobility core-shell NW FETs.

摘要

我们研究了壳层内容和相关的空穴限制对锗-硅（x）锗（1-x）核壳纳米线（NWs）中载流子输运的影响。使用具有不同 Si(x)Ge(1-x)壳层组成（x = 0.5 和 0.7）的 NWs，我们制造了具有高掺杂源/漏的 NW 场效应晶体管（FET），并研究了它们的特性对壳层内容的依赖性。结果表明，在室温下，具有更高（x = 0.7）Si 壳层含量的 NW FET 的迁移率提高了 2 倍，在 77K 时的迁移率提高了 3 倍，而具有更低（x = 0.5）Si 壳层含量的 NW FET 的迁移率则提高了 2 倍。此外，载流子迁移率在具有高 Si 含量的 Ge-Si(x)Ge(1-x)核壳 NW 中表现出更强的温度依赖性，表明电荷杂质散射减少。这些结果表明，载流子限制在实现高迁移率核壳 NW FET 中起着关键作用。