Thin SiGe virtual substrates for Ge heterostructures integration on silicon

Cecchi, S., Gatti, E., Chrastina, D., Frigerio, J., Müller Gubler, E., Paul, D.J. , Guzzi, M. and Isella, G. (2014) Thin SiGe virtual substrates for Ge heterostructures integration on silicon. Journal of Applied Physics, 115(9), 093502. (doi: 10.1063/1.4867368)

Abstract

The possibility to reduce the thickness of the SiGe virtual substrate, required for the integration of Ge heterostructures on Si, without heavily affecting the crystal quality is becoming fundamental in several applications. In this work, we present 1 lm thick Si1− x Ge buffers (with x>0.7) having different designs which could be suitable for applications requiring a thin virtual substrate. The rationale is to reduce the lattice mismatch at the interface with the Si substrate by introducing composition steps and/or partial grading. The relatively low growth temperature (475°C) makes this approach appealing for complementary metal-oxide-semiconductor integration. For all the investigated designs, a reduction of the threading dislocation density compared to constant composition Si1− x Ge layers was observed. The best buffer in terms of defects reduction was used as a virtual substrate for the deposition of a Ge/SiGe multiple quantum well structure. Room temperature optical absorption and photoluminescence analysis performed on nominally identical quantum wells grown on both a thick graded virtual substrate and the selected thin buffer demonstrates a comparable optical quality, confirming the effectiveness of the proposed approach.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Paul, Professor Douglas
• Authors: Cecchi, S., Gatti, E., Chrastina, D., Frigerio, J., Müller Gubler, E., Paul, D.J., Guzzi, M., and Isella, G.
• Subjects: T Technology > T Technology (General)
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Research Group: Semiconductor Devices
• Journal Name: Journal of Applied Physics
• Publisher: American Institute of Physics
• ISSN: 0021-8979
• ISSN (Online): 1089-7550

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
53353	1	Generate Renewable Energy Efficiently using Nanofabricated Silicon (GREEN Silicon.)	Douglas Paul	See Collaborators (SEE-COLLAB)	UNSPECIFIED	ENG - ENGINEERING ELECTRONICS & NANO ENG