liu.seSearch for publications in DiVA
Change search
ReferencesLink to record
Permanent link

Direct link
Growth and characterization of Ge quantum dots on SiGe-based multilayer structures
Linköping University, Department of Physics, Chemistry and Biology.
2009 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesisAlternative title
Tillväxt och karaktärisering av Ge kvantprickar på SiGe-baserade multilager strukturer (Swedish)
Abstract [en]

Thermistor material can be used to fabricate un-cooled IR detectors their figure of merit is the Temperature Coefficient of Resistance (TCR). Ge dots in Si can act as a thermistor material and they have a theoretical TCR higher than for SiGe layers but they suffer from intermixing of Si into the Ge dots. Ge dots were grown on unstrained or strained Si layers and relaxed or strained SiGe layers at temperatures of 550 and 600°C by reduced pressure chemical vapor deposition (RPCVD). Both single and multilayer structures where grown and characterized. To achieve a strong signal in a thermal detector a uniform shape and size distribution of the dots is desired. In this thesis work, an endeavor has been to grow uniform Ge dots with small standard deviation of their size. Scanning electron microscopy (SEM) and Atomic force microscopy (AFM) have been used to characterize the size and shape distribution of Ge dots. Ge contents measured with Raman spectroscopy are higher at lower growth temperatures. Simulation of TCR for the most uniform sample grown at 600°C give 4.43%/K compared to 3.85%/K for samples grown at 650°C in a previous thesis work.

Strained surfaces increases dot sizes and make dots align in crosshatched pattern resulting in smaller density, this effect increases with increasing strain.

Strain from buried layers of Ge dots in a multilayer structure make dots align vertically. This alignment of Ge dots was very sensitive to the thickness of the Si barrier layer. The diameter of dots increase for each period in a multilayer structure. When dots are capped by a Si layer at the temperature of 600°C intermixing of Si into the Ge dot occurs and the dot height decrease.

Place, publisher, year, edition, pages
2009. , 72 p.
Keyword [en]
Ge dots, SiGe, Thermistor, IR-detector, Bolometer, intermixing, strain
National Category
Other Engineering and Technologies not elsewhere specified
URN: urn:nbn:se:liu:diva-16674ISRN: LITH-IFM-A-EX--09/2055--SEOAI: diva2:201075
2009-02-13, Röntgen, Fysikhuset, Linköpings universitet 581 83, Linköping, 13:15 (English)
Available from: 2009-03-03 Created: 2009-02-10 Last updated: 2009-03-03Bibliographically approved

Open Access in DiVA

fulltext(0 kB)237 downloads
File information
File name FULLTEXT01.pdfFile size 0 kBChecksum SHA-512
Type fulltextMimetype application/pdf

By organisation
Department of Physics, Chemistry and Biology
Other Engineering and Technologies not elsewhere specified

Search outside of DiVA

GoogleGoogle Scholar
Total: 237 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 247 hits
ReferencesLink to record
Permanent link

Direct link