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.
Original language | English |
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Pages (from-to) | 6257-6260 |
Number of pages | 4 |
Journal | Applied Surface Science |
Volume | 254 |
Issue number | 19 |
DOIs | |
State | Published - 30 Jul 2008 |
Keywords
- Carrier gas effect
- Hydrogen passivation
- SiGe quantum dot
- Surface mobility
- UHVCVD