A partly-contacted epitaxial lateral overgrowth method applied to GaN material.

Ming Xiao,Hengsheng Shan,Xiaoling Duan,Jing Ning,Ting Yu,Yue Hao,Jincheng Zhang

doi:10.1038/srep23842

Ming Xiao, Hengsheng Shan + Show 5 more

Open Access

https://doi.org/10.1038/srep23842

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Journal: Scientific Reports	Publication Date: Apr 1, 2016
Citations: 10	License type: CC BY 4.0

Affiliation: Xidian University

Abstract

We have discussed a new crystal epitaxial lateral overgrowth (ELO) method, partly-contacted ELO (PC-ELO) method, of which the overgrowth layer partly-contacts with underlying seed layer. The passage also illustrates special mask structures with and without lithography and provides three essential conditions to achieve the PC-ELO method. What is remarkable in PC-ELO method is that the tilt angle of overgrowth stripes could be eliminated by contacting with seed layer. Moreover, we report an improved monolayer microsphere mask method without lithography of PC-ELO method, which was used to grow GaN. From the results of scanning electron microscopy, cathodoluminescence, x-ray diffraction (XRD), transmission electron microscopy, and atomic force microscope (AFM), overgrowth layer shows no tilt angle relative to the seed layer and high quality coalescence front (with average linear dislocation density <6.4 × 103 cm−1). Wing stripes peak splitting of the XRD rocking curve due to tilt is no longer detectable. After coalescence, surface steps of AFM show rare discontinuities due to the low misorientation of the overgrowth regions.

Highlights

Epitaxial lateral overgrowth (ELO) has been shown to significantly reduce extended defect densities in heteroepitaxy GaN film[1,2,3,4,5]
In order to reduce the threading dislocation density (TDD) of the heteroepitaxy GaN film, some advances in nano-ELOG and the related technique of nano-pendeo epitaxial growth of GaN have been widely reported in the period circa 2005 to about 2013
We discuss a new epitaxial lateral overgrowth (ELO) method, of which the overgrown regions are partly-contacted with underlying seed layer to suppress “wing tilts” and reduce coalescence threading dislocations (TDs)

Summary

Introduction

Epitaxial lateral overgrowth (ELO) has been shown to significantly reduce extended defect densities in heteroepitaxy GaN film[1,2,3,4,5]. We discuss a new ELO method, of which the overgrown regions are partly-contacted with underlying seed layer to suppress “wing tilts” and reduce coalescence threading dislocations (TDs).

Results

Conclusion