Time-Efficient High-Resolution Large-Area Nano-Patterning of Silicon Dioxide

Li Lin,Haiyan Ou,Yiyu Ou,Berit Herstrøm,Martin Aagesen,Flemming Jensen

doi:10.3390/mi8010013

Abstract

A nano-patterning approach on silicon dioxide (SiO2) material, which could be used for the selective growth of III-V nanowires in photovoltaic applications, is demonstrated. In this process, a silicon (Si) stamp with nanopillar structures was first fabricated using electron-beam lithography (EBL) followed by a dry etching process. Afterwards, the Si stamp was employed in nanoimprint lithography (NIL) assisted with a dry etching process to produce nanoholes on the SiO2 layer. The demonstrated approach has advantages such as a high resolution in nanoscale by EBL and good reproducibility by NIL. In addition, high time efficiency can be realized by one-spot electron-beam exposure in the EBL process combined with NIL for mass production. Furthermore, the one-spot exposure enables the scalability of the nanostructures for different application requirements by tuning only the exposure dose. The size variation of the nanostructures resulting from exposure parameters in EBL, the pattern transfer during nanoimprint in NIL, and subsequent etching processes of SiO2 were also studied quantitatively. By this method, a hexagonal arranged hole array in SiO2 with a hole diameter ranging from 45 to 75 nm and a pitch of 600 nm was demonstrated on a four-inch wafer.

Highlights

Time-efficient high-resolution large-area nano-patterning of SiO2 is crucial for producing cost-effective and high-efficiency tandem GaAsP nanopillars on Si solar cells since the diameters of predefined nanoholes in the SiO2 layer determine the diameters of selectively grown GaAsP nanowires [1,2,3]
In addition to this specific application, nano-patterning methods are extensively employed in the field of light emitting diodes (LEDs) to improve light extraction efficiency [4,5], to enhance the internal quantum efficiency [6,7] and to tune the emission peak wavelength [8,9]
Nowadays, nanoimprint lithography (NIL) assisted with an electron-beam lithography (EBL)-based stamp is still widely used in applications demanding high resolution with a nanofeature size as small as 100 nm [22,23]

Summary

Introduction

Time-efficient high-resolution large-area nano-patterning of SiO2 is crucial for producing cost-effective and high-efficiency tandem GaAsP nanopillars on Si solar cells since the diameters of predefined nanoholes in the SiO2 layer determine the diameters of selectively grown GaAsP nanowires [1,2,3]. Various methods of nano-patterning have been investigated including electron-beam lithography (EBL) [10,11], nanoimprint lithography (NIL) [12,13], nanosphere lithography [14,15,16], and rapid thermal annealing of a thin metal layer [17,18,19] These methods are usually limited by either low time efficiency, high process cost, or low resolution. Nowadays, NIL assisted with an EBL-based stamp is still widely used in applications demanding high resolution with a nanofeature size as small as 100 nm [22,23] These papers only focus on the nanoimprint technology, without investigating the low throughput.

Method

Results and Discussion

To shows

Diameter distribution measuredfrom from top-view top-view SEM of of

Conclusions