Monolithic heteroepitaxial integration of III-V semiconductor lasers on Si substrates

Monolithic optoelectronic integration on silicon-based integrated circuits has to date been limited to date by the large material differences between silicon (Si) and the direct-bandgap GaAs compounds from which optoelectronic components are fabricated. Graded Ge/GeSi buffer layers grown on standard Si substrates have been shown to produce near-lattice matched virtual substrates for GaAs integration on Si. This study investigated the crystal growth conditions and device fabrication techniques necessary for successful GaAs-based laser integration on Ge/GeSi buffer layers on Si substrates. The nucleation conditions for GaAs on Ge/GeSi/Si substrates have been comprehensively examined. High-temperature ( 2 700⁰ C) initiation with properly chosen V/III gas flow ratio yields high-quality, stacking fault-free GaAs films on Ge/GeSi/Si substrates, but also encourages the vapor-phase transport of Ge from the substrate into the active regions of integrated GaAs devices. A new two-step GaAs nucleation process was developed that enabled the first demonstration of high-quality Ge-free GaAs light-emitting diodes on Ge/GeSi/Si substrates. The large thermal expansion mismatch between Si, Ge, and GaAs introduces additional strain to integrated device layers on Ge/GeSi/Si substrates grown at high temperatures. This study conclusively demonstrated the link between thermal mismatch strain and increased misfit dislocation formation in InxGa(lx)As/GaAs quantum well structures integrated on Ge/GeSi/Si substrates.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Materials Science and Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2002

Author dc:creator

• Groenert, Michael

Advisor dc:contributor.advisor

• Eugene A. Fitzgerald.

• Materials Science and Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/16876

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/16876