Ge/Si nanowire heterostructures as high-performance field-effect transistors
Ge/Si nanowire heterostructures as high-performance field-effect transistors
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DOI：
10.1038/nature04796
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发表时间：
2006-05-25
期刊：
影响因子：
64.8
通讯作者：
Lieber, Charles M.
中科院分区：
文献类型：
--
作者：
Xiang, Jie;Lu, Wei;Lieber, Charles M.
半导体碳纳米管（1,2）和纳米线(3)是平面金属氧化物半导体场效应晶体管（mosfet）(4)的潜在替代品，例如，由于它们独特的电子结构和减少了一维量子限制效应引起的载流子散射（1,5）。研究表明，碳纳米管1,6和Ge/Si核/壳纳米线在室温下都具有较长的载流子平均自由程(7)。在碳纳米管场效应管的情况下，已经制造出接近弹道极限的器件(8)。然而，高性能碳纳米管场效应管的应用一直受到阻碍，因为难以生产均匀的半导体纳米管，这是一个不限制纳米线的因素，而纳米线已被制备成具有可重复电子特性的高产量，这是大规模集成系统所需要的（3,9,10）。然而，纳米线场效应晶体管（nwfet）是否真的能胜过它们的平面对应物还不清楚(4)。在这里，我们报告了在顶栅几何结构中使用高kappa介电体配置为场效应管的Ge/Si核/壳纳米线异质结构的研究。Ge/Si纳米线异质结构中干净的一维空穴气体(7)和具有高kappa介电体的增强栅极耦合使fet的比例跨导值（3.3 mS μ m(-1)）和导通电流（2.1 mA μ m(-1)）比最先进的mosfet高三到四倍，并且是nwfet上获得的最高值。此外，对器件应用的关键指标——固有开关延迟tau = CV/I的比较（4,11）表明，Ge/Si nwfet的性能与类似长度的碳纳米管fet相当，并且大大超过了平面硅mosfet的长度相关缩放。
Semiconducting carbon nanotubes(1,2) and nanowires(3) are potential alternatives to planar metal-oxide-semiconductor field-effect transistors (MOSFETs)(4) owing, for example, to their unique electronic structure and reduced carrier scattering caused by one-dimensional quantum confinement effects(1,5). Studies have demonstrated long carrier mean free paths at room temperature in both carbon nanotubes1,6 and Ge/Si core/shell nanowires(7). In the case of carbon nanotube FETs, devices have been fabricated that work close to the ballistic limit(8). Applications of high-performance carbon nanotube FETs have been hindered, however, by difficulties in producing uniform semiconducting nanotubes, a factor not limiting nanowires, which have been prepared with reproducible electronic properties in high yield as required for large-scale integrated systems(3,9,10). Yet whether nanowire field-effect transistors (NWFETs) can indeed outperform their planar counterparts is still unclear(4). Here we report studies on Ge/Si core/shell nanowire heterostructures configured as FETs using high-kappa dielectrics in a top-gate geometry. The clean one-dimensional hole-gas in the Ge/Si nanowire heterostructures(7) and enhanced gate coupling with high-kappa dielectrics give high-performance FETs values of the scaled transconductance (3.3 mS mu m(-1)) and on-current (2.1 mA mu m(-1)) that are three to four times greater than state-of-the-art MOSFETs and are the highest obtained on NWFETs. Furthermore, comparison of the intrinsic switching delay, tau = CV/I, which represents a key metric for device applications(4,11), shows that the performance of Ge/Si NWFETs is comparable to similar length carbon nanotube FETs and substantially exceeds the length-dependent scaling of planar silicon MOSFETs.