Nanoscale structural defects in oblique Ar+ sputtered Si(111) surfaces

Divya Gupta,Mahak Chawla,Rahul Singhal,Sanjeev Aggarwal

doi:10.1038/s41598-019-52099-4

Divya Gupta, Mahak Chawla + Show 2 more

Open Access

https://doi.org/10.1038/s41598-019-52099-4

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Abstract

The present endeavor investigates the controlled surface modifications and evolution of self-assembled nano-dimensional defects on oblique Ar+ sputtered Si(111) surfaces which are important substrates for surface reconstruction. The defect formation started at off-normal incidences of 50° and then deflates into defined defect zones with decrease in oblique incidence, depending strongly on angle of ion incidence. Interestingly, it is observed that mean size & height decreases while average density of these defects increases with decreasing oblique incidence. Non-linear response of roughness of irradiated Si(111) with respect to oblique incidence is observed. Crystalline (c-Si) to amorphous (a-Si) phase transition under oblique argon ion irradiation has been revealed by Raman spectroscopy. Our analysis, thus, shows that high dose argon ion irradiation generates of self-assembled nano-scale defects and surface vacancies & their possible clustering into extended defect zones. Explicitly, ion beam-stimulated mass transport inside the amorphous layers governs the observed defect evolution. This investigation of crystalline (c-Si) coupled with amorphous (a-Si) phases of nano-structured surfaces provides insight into the potential applications in the nano-electronic and optoelectronic devices thus, initiating a new era for fabricating multitude of novel structures.

Highlights

In integrated circuit technology, silicon is nowadays exploited as a potential candidate for the production of various nano-scale applications like optoelectronic devices, IR detectors, and FET’s1
Our findings provide a reliable way for controlled surface modification of Si(111) surfaces under oblique ion beam irradiation
Raman scattering reveal that c-Si and assess the contribution from crystalline peak (a-Si) peaks shift towards lower wavenumber followed by line-width narrowing with respect to decrease in oblique incidence

Summary

Introduction

Silicon is nowadays exploited as a potential candidate for the production of various nano-scale applications like optoelectronic devices, IR detectors, and FET’s1. Height and density distribution of nanoscale defects & roughness of Si(111) surfaces as a function of oblique incidence. The corresponding decrease in roughness as a function of oblique incidence point towards ordering of nanoscale defects evolved on the surfaces of irradiated specimens (Fig. 2).

Results

Conclusion