1. Growth and Characterization of GeSn for Infrared Imaging
Student: Randy Quinde Mentor: Dr. Fisher Yu (ELEG)
Undergraduate School / Major: University of Minnesota / Electrical Engr
Microelectronics
Photonics
Background/Relevance
Current semiconductor material within infrared red (IR) devices are expensive for manufacturing and fabrication.
Growing group IV elements together, such as germanium tin (GeSn), within chemical vapor deposition (CVD) machines have could reduce the cost and improve the quality of IR devices.
Innovation
Implementing GeSn within todays technology would greatly reduce the prices of cellphones, computers, and other everyday devices.
Lasing GeSn could improve the quality and speed of the internet as studies have shown.
Approach
Analyze and compare GeSn samples to find parameters of growth of GeSn on the UHV-CVD machine
Grow GeSn within Ultra High Vacuum- Chemical Vapor Deposition (UHV-CVD) by disbursing germane and tin tetrachloride into chambers
Find the thickness of the GeSn samples by using the VASE ellipsometer
Characterize the GeSn samples using photoluminescence (PL) and Raman spectroscopy to gather information on the sample’s quality, bandgap, strain, and crystallinity.
UHV-CVD
Key Results
GeSn was grown at 350oC, 1 torr, 25 sccm of argon(Ar), 10 sccm of germane (GeH4), and 0.02 sccm of tin tetrachloride at varying times.
Nucleation occurred between minutes of growth of GeSn
Growth rate shows that 1 µm would take approximately 200 minutes.
Conclusions
The growth of GeSn in the UHV-CVD machine was successfully grown in the set parameters.
Growths performed with UHV-CVD can now determine and control the thickness of material depending on the length of time.
Characterization results indicate the material had low tin (Sn) incorporation, direct bandgap energy, and low optical properties.
Research is still needed to study growth rate of GeSn at different temperatures, pressures, and flow rates for UHV-CVD machine.
Acknowledgements to Dr. Shui-Qing Yu, Dr. Aboozar Moshleh, Perry C. Grant, Sattar Al-Kabi, Joshua M. Grant, Wei Dou, Bader Alharthi, and Seyed Amir Ghetmiri for their support and assistance.
Research Funded by National Science Foundation REU Grant # EEC
Summer 2015