Journal of the Computational Structural Engineering Institute of Korea (한국전산구조공학회논문집)

Computational Structural Engineering Institute of Korea (한국전산구조공학회)
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A Numerical Study on the Alignment of Surface Structures on Silicon-germanium Thin Films under a Localized Modulation of Surface Diffusivity

표면확산계수의 국부적 제어를 통한 실리콘-게르마늄 박막상 표면구조물의 정렬에 관한 수치해석적 연구

  • Kim, Yun Young (Department of Mechanical Engineering, Northwestern University) ;
  • Han, Bong Koo (Department of Civil Engineering, Seoul National University of Science and Technology)
  • 김윤영 (노스웨스턴대학교 기계공학과) ;
  • 한봉구 (서울과학기술대학교 건설시스템디자인공학과)
  • Received : 2014.10.31
  • Accepted : 2014.12.16
  • Published : 2015.02.28
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Abstract

This paper presents a numerical study on the alignment of ridge-like surface structures evolving on silicon-germanium thin films under localized modulation of surface diffusivity. A situation is considered in which the surface diffusion of film material is selectively promoted such that its morphology is perturbed to periodic patterns. To simulate the growth behavior, a governing equation is formulated taking the surface chemical potential into account, and its solution is numerically sought using a finite-difference method. Results show that an initially planar surface coalesces upon the diffusivity modulation, and the surface structures can be aligned by changing the frequency of modulation condition. This research suggests a bottom-up fabrication technique that can manage the regularity of surface structures for thin film devices.

본 논문에서는 헤테로 애피택시(heteroepitaxy) 박막의 표면확산계수를 국부적으로 제어하여 표면에서 형성되는 나노구조물이 정렬되는 과정을 수치해석적으로 연구하였다. 격자 불일치 물질계(lattice-mismatched materials system)의 탄성변형에너지와 표면자유에너지, 그리고 습윤에너지를 고려하여 박막의 변형거동에 대한 지배방정식을 도출하였으며, 확산계수의 활성화 조건이 성장에 미치는 영향을 살펴보았다. 해석결과는 주기함수 형식으로 표면확산계수를 제어하면 표면구조물이 배열 형태로 정렬됨을 나타내며, 이는 노광 및 식각 과정을 거쳐야 하는 포토리소그래피(photolithography)로부터 탈피한 바텀업(bottom-up) 방식의 공정방법에 규칙성을 부여하여 차세대 나노기기의 개발에 일조할 것으로 기대된다.

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References

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