纳米压印多孔硅模板的研究

纳米压印模板通常采用极紫外光刻、聚焦离子束光刻和电子束光刻等传统光刻技术制备,成本较高.寻找一种简单、低成本的纳米压印模板制备方法以提升纳米压印光刻技术的应用成为研究的重点与难点.本文以多孔氧化铝为母模板,采用纳米压印光刻技术对纳米多孔硅模板的制备进行了研究.在硅基表面成功制备出纳米多孔阵列结构,孔间距为350—560 nm,孔径在170—480 nm,孔深为200 nm.在激发波长为514 nm时,拉曼光谱的测试结果表明,相对于单面抛光的硅片,纳米多孔结构的硅模板拉曼光强有了约12倍左右的提升,对提升硅基光电器件的应用具有重要的意义.最后,利用多孔硅模板作为纳米压印母模板,通过热压印技术,成功制备出了聚合物纳米柱软模板.

Study on porous silicon template for nanoimprint lithography

The template for naoimprint lithography having a nano-sized structure was usually fabricated by traditional lithography such as extreme ultraviolet (EUV) lithography, focused ion beam (FIB) lithography, electron beam (EB) lithography. However, these approaches are always time-consuming and inefficiency which limits the potential application in nanoimprint lithography. To find a simple and low-cost method to fabricate the mold for nanoimprint lithography, and to improve the application in nanoimprint lithography have become the research focus. Instead of being formed by traditional lithography, the anodic aluminum oxide (AAO), with highly regular structures and high pore density, is the mold to achieve periodic structures for nanoimprint lithography. In this work, we successfully transfer a 2D nanoporous array structure to the Si surface via the nanoimprint lithography and AAO. The pore diameter and the interpore distance of the porous silicon (PS) are well consistent with that of AAO template. The interval, the diameter, and the height of the hexagonal array structure are 350–560 nm, 170–480 nm, and 200 nm, respectively. We have tested the Raman spectrum under the excitation by lasers of wavelength 514 nm. According to the results, two samples each exhibits a peak at 520 cm^-1 and no frequency shift is observed with the Si characteristic Raman peak, indicating that the PS was not extensively damaged by the ICP etching process. Raman intensity in the structured Si is almost enhanced by a factor of 12 as compared with the case on polished Si, which will greatly benefit the application of Si-based optical devices. Thus, we have realized the replica of the PS template and obtained a nanopillar soft template via the hot embossing lithography.