The fabrication of Si0.7Ge0.3 sub-10 nm nanochannels in gate-all-around devices requires a highly selective Si isotropic etching process. The etching of Si selectively to Si0.7Ge0.3 with CF4/N2/O2 downstream plasma has been investigated using various morphological and surface characterization techniques. Conditions such as 400 W microwave power, 700 mTorr pressure, 25 °C chuck temperature, and 22% CF4:22% N2:56% O2 feed gas mixture were found to be optimum for selectivity and etch rates. X-ray photoelectron spectroscopy showed that, during the etching process, a highly reactive 8 nm thick SiOxFy layer is formed on Si. Meanwhile, a 2 nm thick passivation layer is observed on SiGe. The latter is a mixture of SiOxFy and GeOxFy species that protected the alloy from etching. The process selectivity was improved by investigating different wet and dry oxidant treatments prior to etching. The dry oxidant treatment gives the best results in terms of selectivity. These results obtained on blanket wafers have been validated on pattern wafers. Scanning electron microscopy demonstrated that SiGe nanowires were fully released with a high selectivity after dry oxidation followed by the etching process.
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Isotropic dry etching of Si selectively to Si0.7Ge0.3 for CMOS sub-10 nm applications
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Research Article|
March 09 2020
Isotropic dry etching of Si selectively to Si0.7Ge0.3 for CMOS sub-10 nm applications
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Sana Rachidi;
Sana Rachidi
a)
Université Grenoble Alpes and CEA, LETI
, Grenoble 38000, France
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Alain Campo;
Alain Campo
b)
Université Grenoble Alpes and CEA, LETI
, Grenoble 38000, France
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Virginie Loup;
Virginie Loup
c)
Université Grenoble Alpes and CEA, LETI
, Grenoble 38000, France
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Christian Vizioz;
Christian Vizioz
d)
Université Grenoble Alpes and CEA, LETI
, Grenoble 38000, France
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Jean-Michel Hartmann;
Jean-Michel Hartmann
e)
Université Grenoble Alpes and CEA, LETI
, Grenoble 38000, France
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Sébastien Barnola;
Sébastien Barnola
f)
Université Grenoble Alpes and CEA, LETI
, Grenoble 38000, France
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Nicolas Posseme
Nicolas Posseme
g)
Université Grenoble Alpes and CEA, LETI
, Grenoble 38000, France
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Sana Rachidi
a)
Université Grenoble Alpes and CEA, LETI
, Grenoble 38000, France
Alain Campo
b)
Université Grenoble Alpes and CEA, LETI
, Grenoble 38000, France
Virginie Loup
c)
Université Grenoble Alpes and CEA, LETI
, Grenoble 38000, France
Christian Vizioz
d)
Université Grenoble Alpes and CEA, LETI
, Grenoble 38000, France
Jean-Michel Hartmann
e)
Université Grenoble Alpes and CEA, LETI
, Grenoble 38000, France
Sébastien Barnola
f)
Université Grenoble Alpes and CEA, LETI
, Grenoble 38000, France
Nicolas Posseme
g)
Université Grenoble Alpes and CEA, LETI
, Grenoble 38000, France
a)
Electronic mail: [email protected]
b)
Electronic mail: [email protected]
c)
Electronic mail: [email protected]
d)
Electronic mail: [email protected]
e)
Electronic mail: [email protected]
f)
Electronic mail: [email protected]
g)
Electronic mail: [email protected]
J. Vac. Sci. Technol. A 38, 033002 (2020)
Article history
Received:
December 19 2019
Accepted:
February 21 2020
Citation
Sana Rachidi, Alain Campo, Virginie Loup, Christian Vizioz, Jean-Michel Hartmann, Sébastien Barnola, Nicolas Posseme; Isotropic dry etching of Si selectively to Si0.7Ge0.3 for CMOS sub-10 nm applications. J. Vac. Sci. Technol. A 1 May 2020; 38 (3): 033002. https://doi.org/10.1116/1.5143118
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