A study of electron traps in vapor phase epitaxial gallium arsenide grown in the presence of oxygen
A detailed analysis of the measurement technique known as constant capacitance deep level transient spectroscopy is presented, which includes an accurate treatment of large and inhomogeneous defect densities, and which allows a precise determination of deep level concentrations and activation energies. The design and construction of the automated measurement apparatus are described, and the computer programs for the data acquisition and analysis are included. The history of adding oxygen during the growth of GaA~ is discussed and the motivation for this study is provided. Then, the effects of the addition of oxygen on important electrical and optical properties of the layers are presented. These include a reduction in free electron concentration, an increase in electron mobility, a reduction in both shallow donor and acceptor concentrations, and essentially no effect on the concentrations of electron traps. The behavior of these optical and electrical properties with the addition of both silane and oxygen is also studied to provide additional information about the role of oxygen in the suppression of silicon incorporation during GaAs growth. Finally, some conclusions are drawn about the usefulness of this technique for certain technological applications.
electron traps, vapor phase epitaxial gallium arsenide, constant capacitance deep layer transient spectroscopy, inhomogeneous defect densities
University of Illinois - Urbana-Champaign
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