Alternatives for Doping in Nanoscale Field‐Effect Transistors
Alternatives for Doping in Nanoscale Field‐Effect Transistors
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DOI：
10.1002/pssa.201700969
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发表时间：
2018-04
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通讯作者：
Felix Riederer;T. Grap;Sergej Fischer;M. Mueller;Daichi Yamaoka;Bin Sun;Charu Gupta;K. Kallis;J. Knoch
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文献类型：
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作者：
Felix Riederer;T. Grap;Sergej Fischer;M. Mueller;Daichi Yamaoka;Bin Sun;Charu Gupta;K. Kallis;J. Knoch
在本文中，研究了纳米级场效应晶体管（FET）中杂质掺杂的替代方案。讨论是基于传统和隧道场效应晶体管。由于介电失配或量子化，随机掺杂剂的影响，和性能上的简并水平的掺杂剂失活的影响进行了讨论。作为金属-半导体-接触的替代方案，研究了栅控掺杂和界面工程方法。适当的器件功能的主要要求之一是接触中存在带隙。因此，金属-半导体接触不太适合，因为它们导致双极操作，增加了泄漏，并导致导通状态性能恶化。通过栅控掺杂，电极被用来创建掺杂区域，留下原始的带隙。此外，它还支持nFET、pFET和隧道FET操作的可重构器件。此外，利用多个纳米级栅极，静电掺杂允许在纳米级上操纵器件内的电势。实验演示了这种器件的三门和多门结构。最后，界面工程方法允许通过调整金属和半导体之间的半导体绝缘体来将金属接触电极与源极/漏极接触中几乎未修改的带隙组合，从而产生准掺杂接触，其极性取决于接触金属的功函数。
In the present article, alternatives to impurity doping in nanoscale field‐effect transistors (FETs) are investigated. The discussion is based on conventional and tunnel FETs. The impact of dopant deactivation due to dielectric mismatch or quantization, random dopant effects, and the degeneracy level on the performance is discussed. As alternatives metal‐semiconductor‐contacts, gate‐controlled doping and an interface engineering approach are studied. One of the main requirements for proper device functionality is the existence of a band gap in the contacts. Thus, metal‐semiconductor contacts are less suited since they lead to ambipolar operation with increased leakage and to a deteriorated on‐state performance. With gate‐controlled doping, electrodes areused to create doped regions leaving behind a pristine band gap. Moreover, it enables reconfigurable devices with nFET, pFET and tunnel FET operation. Furthermore, with multiple nanoscale gates, electrostatic doping allows manipulating the potential within the device on the nanoscale. Experimental demonstrations of such devices with triple‐gates and multiple gate structures are presented. Finally, the interface engineering approach allows combining a metallic contact electrode with an almost unmodified band gap in the source/drain contacts by adjusting an ultrathin insulator in‐between metal and semiconductor yielding quasi‐doped contacts whose polarity depends on the work function of contact metal.