The Effect of Doping on the Digital Etching of Silicon-Selective Silicon–Germanium Using Nitric Acids
In: Nanomaterials, Jg. 11 (2021-05-01), Heft 5
Online
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Zugriff:
Gate-all-around (GAA) field-effect transistors have been proposed as one of the most important developments for CMOS logic devices at the 3 nm technology node and beyond. Isotropic etching of silicon–germanium (SiGe) for the definition of nano-scale channels in vertical GAA CMOS and tunneling FETs has attracted more and more attention. In this work, the effect of doping on the digital etching of Si-selective SiGe with alternative nitric acids (HNO3) and buffered oxide etching (BOE) was investigated in detail. It was found that the HNO3 digital etching of SiGe was selective to n+-Si, p+-Si, and intrinsic Si. Extensive studies were performed. It turned out that the selectivity of SiGe/Si was dependent on the doped types of silicon and the HNO3 concentration. As a result, at 31.5% HNO3 concentration, the relative etched amount per cycle (REPC) and the etching selectivity of Si0.72Ge0.28 for n+-Si was identical to that for p+-Si. This is particularly important for applications of vertical GAA CMOS and tunneling FETs, which have to expose both the n+ and p+ sources/drains at the same time. In addition, the values of the REPC and selectivity were obtained. A controllable etching rate and atomically smooth surface could be achieved, which enhanced carrier mobility.
Titel: |
The Effect of Doping on the Digital Etching of Silicon-Selective Silicon–Germanium Using Nitric Acids
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Autor/in / Beteiligte Person: | Zhang, Yongkui ; Zeng, Chuanbin ; Huang, Weixing ; Li, Yangyang ; Wang, Guilei ; Lu, Shunshun ; Xie, Lu ; Kong, Zhenzhen ; Wang, Qi ; Liu, Ziyi ; Lin, Hongxiao ; Zhu, Huilong ; Ai, Xuezheng ; Li, Junjie ; Radamson, Henry H. ; Liu, Yongbo ; Li, Chen ; Su, Jiale |
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Zeitschrift: | Nanomaterials, Jg. 11 (2021-05-01), Heft 5 |
Veröffentlichung: | MDPI, 2021 |
Medientyp: | unknown |
ISSN: | 2079-4991 (print) |
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