Carrier gas effects on the SiGe quantum dots formation
Journal
Applied Surface Science
Journal Volume
254
Journal Issue
19
Pages
6257-6260
Date Issued
2008
Author(s)
Abstract
SiGe quantum dots (QDs) grown by ultra-high vacuum chemical vapor deposition using H 2 and He carrier gases are investigated and compared. SiGe QDs using He carrier gas have smaller dot size with a better uniformity in terms of dot height and dot base as compared to the H 2 carrier gas. There is a higher Ge composition and less compressive strain in the SiGe QDs grown in He than in H 2 as measured by Raman spectroscopy. The Ge content is higher for He growth than H 2 growth due to hydrogen induced Si segregation and the lower interdiffusivity caused by the more strain relaxation in the He-grown SiGe dots. The photoluminescence also confirms more compressive strain for H 2 growth than He growth. Hydrogen passivation and Ge-H cluster formation play an important role in the QDs growth. © 2008 Elsevier B.V. All rights reserved.
Type
journal article