Characterization of OMVPE-grown GaSb-based epilayers using in situ reflectance and ex situ TEM

The focus of this thesis was to investigate and characterize GaSb, GaInAsSb, and AlGaAsSb epilayers grown by organometallic vapor phase epitaxy (OMVPE). These epilayers were principally characterized using in situ spectral reflectance and ex situ transmission electron microscopy (TEM). An in situ spectral (380-1100 nm) reflectance monitoring system was designed and fitted to the OMVPE reactor. It was determined that longer wavelengths are more useful for quantitative growth rate analysis, while shorter wavelengths are more sensitive to the GaSb substrate oxide desorption process. It was also determined that the GaInAsSb and AlGaAsSb alloy compositions could be determined accurately using in situ reflectance ratios. Use of the in situ reflectance monitor to efficiently perform necessary reactor/growth calibrations was also demonstrated. Analytic functions were used to model the refractive indices of GaSb, AlGaAsSb, and GaInAsSb. Specifically, Adachi's Model Dielectric Function [1, 2] was curve-fit to data for GaSb between 400 and 1000 nm, and fourth-order polynomials were fit to data for GaSb and GaInAsSb between 1 and 3 gnm. A linear interpolation of binary functions was used to generate a refractive index model for AlGaAsSb between 1 and 3 m as a function of Al fraction. These models were helpful in interpreting in situ reflectance data, and also in designing distributed Bragg reflectors. Phase separation in GaInAsSb was studied using TEM. A wide range of microstructures was observed, from nearly homogeneous to strongly phase separated.

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

2001

Author dc:creator

• Vineis, Christopher J. (Christopher Joseph), 1974-

Advisor dc:contributor.advisor

• Christine A. Wang and Klavs F. Jensen.

• 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/1721.1/8452

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/8452