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Fabrication of HfO2 patterns by laser interference nanolithography and selective dry etching for III-V CMOS application.

Benedicto M, Galiana B, Molina-Aldareguia JM, Monaghan S, Hurley PK, Cherkaoui K, Vazquez L, Tejedor P - Nanoscale Res Lett (2011)

Bottom Line: Pattern transfer to the HfO2 film was carried out by reactive ion beam etching using CF4 and O2 plasmas.A combination of atomic force microscopy, high-resolution scanning electron microscopy, high-resolution transmission electron microscopy, and energy-dispersive X-ray spectroscopy microanalysis was used to characterise the various etching steps of the process and the resulting HfO2/GaAs pattern morphology, structure, and chemical composition.We show that the patterning process can be applied to fabricate uniform arrays of HfO2 mesa stripes with tapered sidewalls and linewidths of 100 nm.

View Article: PubMed Central - HTML - PubMed

Affiliation: Instituto de Ciencia de Materiales de Madrid, CSIC, C/Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain. ptejedor@icmm.csic.es.

ABSTRACT
Nanostructuring of ultrathin HfO2 films deposited on GaAs (001) substrates by high-resolution Lloyd's mirror laser interference nanolithography is described. Pattern transfer to the HfO2 film was carried out by reactive ion beam etching using CF4 and O2 plasmas. A combination of atomic force microscopy, high-resolution scanning electron microscopy, high-resolution transmission electron microscopy, and energy-dispersive X-ray spectroscopy microanalysis was used to characterise the various etching steps of the process and the resulting HfO2/GaAs pattern morphology, structure, and chemical composition. We show that the patterning process can be applied to fabricate uniform arrays of HfO2 mesa stripes with tapered sidewalls and linewidths of 100 nm. The exposed GaAs trenches were found to be residue-free and atomically smooth with a root-mean-square line roughness of 0.18 nm after plasma etching.PACS: Dielectric oxides 77.84.Bw, Nanoscale pattern formation 81.16.Rf, Plasma etching 52.77.Bn, Fabrication of III-V semiconductors 81.05.Ea.

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HR-SEM images of the pattern transfer process. (a) Cross-section view of the etched multilayer structure after pattern transfer to the SiO2 and ARC layers. (b) Cross-section view of the structure after pattern transfer to the HfO2 layer, showing re-deposition of reaction by-products on the sidewalls. (c) View of the nanostructured HfO2 stripes.
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Figure 3: HR-SEM images of the pattern transfer process. (a) Cross-section view of the etched multilayer structure after pattern transfer to the SiO2 and ARC layers. (b) Cross-section view of the structure after pattern transfer to the HfO2 layer, showing re-deposition of reaction by-products on the sidewalls. (c) View of the nanostructured HfO2 stripes.

Mentions: In order to elucidate the origin of the linewidth narrowing observed in the HfO2 stripes with respect to the original resist pattern, a more detailed study of the intermediate etching steps was undertaken. These were characterised by analysing cross-sectional HR-SEM images of the sample at different stages of the nanostructuring process. Figure 3a depicts the cross-section of the sample after pattern transfer to the SiO2 and ARC layers, showing that the SiO2 linewidth (118 nm) has not varied significantly with respect to that of the resist pattern. In addition, the etched sidewalls are vertical, hence, indicating that the pattern was precisely transferred to the SiO2 layer during the first CF4 etching step. By contrast, O2 plasma etching of the ARC layer proceeds with undercut and inclined sidewall (87°) formation, suggesting that some interaction between radicals from the gas phase and the sidewalls has occurred. The linewidth at the bottom of the ARC is consequently reduced (102 nm) with respect to the original resist pattern, as shown in the image.


Fabrication of HfO2 patterns by laser interference nanolithography and selective dry etching for III-V CMOS application.

Benedicto M, Galiana B, Molina-Aldareguia JM, Monaghan S, Hurley PK, Cherkaoui K, Vazquez L, Tejedor P - Nanoscale Res Lett (2011)

HR-SEM images of the pattern transfer process. (a) Cross-section view of the etched multilayer structure after pattern transfer to the SiO2 and ARC layers. (b) Cross-section view of the structure after pattern transfer to the HfO2 layer, showing re-deposition of reaction by-products on the sidewalls. (c) View of the nanostructured HfO2 stripes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211495&req=5

Figure 3: HR-SEM images of the pattern transfer process. (a) Cross-section view of the etched multilayer structure after pattern transfer to the SiO2 and ARC layers. (b) Cross-section view of the structure after pattern transfer to the HfO2 layer, showing re-deposition of reaction by-products on the sidewalls. (c) View of the nanostructured HfO2 stripes.
Mentions: In order to elucidate the origin of the linewidth narrowing observed in the HfO2 stripes with respect to the original resist pattern, a more detailed study of the intermediate etching steps was undertaken. These were characterised by analysing cross-sectional HR-SEM images of the sample at different stages of the nanostructuring process. Figure 3a depicts the cross-section of the sample after pattern transfer to the SiO2 and ARC layers, showing that the SiO2 linewidth (118 nm) has not varied significantly with respect to that of the resist pattern. In addition, the etched sidewalls are vertical, hence, indicating that the pattern was precisely transferred to the SiO2 layer during the first CF4 etching step. By contrast, O2 plasma etching of the ARC layer proceeds with undercut and inclined sidewall (87°) formation, suggesting that some interaction between radicals from the gas phase and the sidewalls has occurred. The linewidth at the bottom of the ARC is consequently reduced (102 nm) with respect to the original resist pattern, as shown in the image.

Bottom Line: Pattern transfer to the HfO2 film was carried out by reactive ion beam etching using CF4 and O2 plasmas.A combination of atomic force microscopy, high-resolution scanning electron microscopy, high-resolution transmission electron microscopy, and energy-dispersive X-ray spectroscopy microanalysis was used to characterise the various etching steps of the process and the resulting HfO2/GaAs pattern morphology, structure, and chemical composition.We show that the patterning process can be applied to fabricate uniform arrays of HfO2 mesa stripes with tapered sidewalls and linewidths of 100 nm.

View Article: PubMed Central - HTML - PubMed

Affiliation: Instituto de Ciencia de Materiales de Madrid, CSIC, C/Sor Juana Inés de la Cruz 3, 28049 Madrid, Spain. ptejedor@icmm.csic.es.

ABSTRACT
Nanostructuring of ultrathin HfO2 films deposited on GaAs (001) substrates by high-resolution Lloyd's mirror laser interference nanolithography is described. Pattern transfer to the HfO2 film was carried out by reactive ion beam etching using CF4 and O2 plasmas. A combination of atomic force microscopy, high-resolution scanning electron microscopy, high-resolution transmission electron microscopy, and energy-dispersive X-ray spectroscopy microanalysis was used to characterise the various etching steps of the process and the resulting HfO2/GaAs pattern morphology, structure, and chemical composition. We show that the patterning process can be applied to fabricate uniform arrays of HfO2 mesa stripes with tapered sidewalls and linewidths of 100 nm. The exposed GaAs trenches were found to be residue-free and atomically smooth with a root-mean-square line roughness of 0.18 nm after plasma etching.PACS: Dielectric oxides 77.84.Bw, Nanoscale pattern formation 81.16.Rf, Plasma etching 52.77.Bn, Fabrication of III-V semiconductors 81.05.Ea.

No MeSH data available.


Related in: MedlinePlus