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Large-scale fabrication of nanopatterned sapphire substrates by annealing of patterned Al thin films by soft UV-nanoimprint lithography.

Cui L, Han JC, Wang GG, Zhang HY, Sun R, Li LH - Nanoscale Res Lett (2013)

Bottom Line: The first comprised a low-temperature oxidation anneal at 450°C for 24 h.This was followed by a high-temperature annealing in the range of 1,000°C and 1,200°C for 1 h to induce growth of the underlying sapphire single crystal to consume the oxide layer.The SEM results indicate that the patterns were retained on sapphire substrates after high-temperature annealing at less than 1,200°C.

View Article: PubMed Central - HTML - PubMed

Affiliation: Shenzhen Graduate School, Harbin Institute of Technology, Shenzhen 518055, People's Republic of China. cuilin0512@gmail.com.

ABSTRACT
Large-scale nanopatterned sapphire substrates were fabricated by annealing of patterned Al thin films. Patterned Al thin films were obtained by soft UV-nanoimprint lithography and reactive ion etching. The soft mold with 550-nm-wide lines separated by 250-nm space was composed of the toluene-diluted polydimethylsiloxane (PDMS) layer supported by the soft PDMS. Patterned Al thin films were subsequently subjected to dual-stage annealing due to the melting temperature of Al thin films (660°C). The first comprised a low-temperature oxidation anneal at 450°C for 24 h. This was followed by a high-temperature annealing in the range of 1,000°C and 1,200°C for 1 h to induce growth of the underlying sapphire single crystal to consume the oxide layer. The SEM results indicate that the patterns were retained on sapphire substrates after high-temperature annealing at less than 1,200°C. Finally, large-scale nanopatterned sapphire substrates were successfully fabricated by annealing of patterned Al thin films for 24 h at 450°C and 1 h at 1,000°C by soft UV-nanoimprint lithography.

No MeSH data available.


Schematic illustration of soft PDMS mold based on quartz master mold.
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Figure 2: Schematic illustration of soft PDMS mold based on quartz master mold.

Mentions: The 2-in. quartz master mold with 250-nm-wide and 150-nm-long lines separated by 550-nm space was fabricated by laser interference lithography and RIE. Prior to replication of soft PDMS mold, the quartz master self-assembled an anti-adhesive monolayer (1H,1H,2H,2H-perfluorodecyltrichloro-silane (FDTS)) by vapor phase deposition to yield a low surface free energy, which is required to detach easily the quartz master and soft PDMS. Figure 2 shows the schematic illustration of the soft PDMS mold based on the quartz master mold. In this paper, we designed a scheme of replication based on the quartz master mold: PDMS was diluted with toluene (60 wt.%) to decrease the viscosity, since the modification of the PDMS ensures high fidelity of pattern features by UV-NIL [18]. The degassed modified PDMS was spin-coated at 3,000 rpm for 30 s on the quartz master mold. After degassing, the quartz master mold with a uniform layer was cured at 120°C for 15 min. Then the degassed PDMS prepolymer (Sylgard 184, Dow Corning, Midland, MI, USA) and its curing agent (1:10 weight) were carefully poured onto the surface, followed by curing at 100°C for 30 min. Afterwards, the 2-in. soft mold, the modified PDMS supported by thick, flexible PDMS layer, was peeled off from the quartz master mold.


Large-scale fabrication of nanopatterned sapphire substrates by annealing of patterned Al thin films by soft UV-nanoimprint lithography.

Cui L, Han JC, Wang GG, Zhang HY, Sun R, Li LH - Nanoscale Res Lett (2013)

Schematic illustration of soft PDMS mold based on quartz master mold.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4225748&req=5

Figure 2: Schematic illustration of soft PDMS mold based on quartz master mold.
Mentions: The 2-in. quartz master mold with 250-nm-wide and 150-nm-long lines separated by 550-nm space was fabricated by laser interference lithography and RIE. Prior to replication of soft PDMS mold, the quartz master self-assembled an anti-adhesive monolayer (1H,1H,2H,2H-perfluorodecyltrichloro-silane (FDTS)) by vapor phase deposition to yield a low surface free energy, which is required to detach easily the quartz master and soft PDMS. Figure 2 shows the schematic illustration of the soft PDMS mold based on the quartz master mold. In this paper, we designed a scheme of replication based on the quartz master mold: PDMS was diluted with toluene (60 wt.%) to decrease the viscosity, since the modification of the PDMS ensures high fidelity of pattern features by UV-NIL [18]. The degassed modified PDMS was spin-coated at 3,000 rpm for 30 s on the quartz master mold. After degassing, the quartz master mold with a uniform layer was cured at 120°C for 15 min. Then the degassed PDMS prepolymer (Sylgard 184, Dow Corning, Midland, MI, USA) and its curing agent (1:10 weight) were carefully poured onto the surface, followed by curing at 100°C for 30 min. Afterwards, the 2-in. soft mold, the modified PDMS supported by thick, flexible PDMS layer, was peeled off from the quartz master mold.

Bottom Line: The first comprised a low-temperature oxidation anneal at 450°C for 24 h.This was followed by a high-temperature annealing in the range of 1,000°C and 1,200°C for 1 h to induce growth of the underlying sapphire single crystal to consume the oxide layer.The SEM results indicate that the patterns were retained on sapphire substrates after high-temperature annealing at less than 1,200°C.

View Article: PubMed Central - HTML - PubMed

Affiliation: Shenzhen Graduate School, Harbin Institute of Technology, Shenzhen 518055, People's Republic of China. cuilin0512@gmail.com.

ABSTRACT
Large-scale nanopatterned sapphire substrates were fabricated by annealing of patterned Al thin films. Patterned Al thin films were obtained by soft UV-nanoimprint lithography and reactive ion etching. The soft mold with 550-nm-wide lines separated by 250-nm space was composed of the toluene-diluted polydimethylsiloxane (PDMS) layer supported by the soft PDMS. Patterned Al thin films were subsequently subjected to dual-stage annealing due to the melting temperature of Al thin films (660°C). The first comprised a low-temperature oxidation anneal at 450°C for 24 h. This was followed by a high-temperature annealing in the range of 1,000°C and 1,200°C for 1 h to induce growth of the underlying sapphire single crystal to consume the oxide layer. The SEM results indicate that the patterns were retained on sapphire substrates after high-temperature annealing at less than 1,200°C. Finally, large-scale nanopatterned sapphire substrates were successfully fabricated by annealing of patterned Al thin films for 24 h at 450°C and 1 h at 1,000°C by soft UV-nanoimprint lithography.

No MeSH data available.