Damage At Reactive Ion Etched MBE Regrown GaAs Interface

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Abstract
In this study, GaAs surface damage resulting from reactive ion etching (RI E) and wet etching was assessed by temperature dependent photoluminescence (PL) and room temperature Raman spectroscopy. Four samples of GaAs grown by molecular beam epitaxy (MBE), etched and then epitaxially regrown were analyzed. Two of these samples were etched reactively, one with HC1 and the other with C12. The third sample was wet etched and the final sample was used as a control. AlI the samples were initially cleaved from the same MBE grown wafer and were regrown together in order to maintain similar growth conditions. To further elucidate the damage, cross-sectional Transmission Electron Microscopy (TEM) was performed on these samples. For all of the samples except the HC1 etched, it was possible to obtain a fit to the temperature dependence of the PL intensity of the exciton. In addition, we found a strong correlation between the samples' relative LO phonon Raman intensity to the relative PL intensities in which the sample etched by HC1 was found to be inferior to the other samples. Further, because of the presence of the "forbidden" TO peak, the Raman spectra indicated the presence of structural defects such as dislocations and twinning. Cross-sectional TEM was used to compare the interface region of the four samples where the damage due to etching and the quality of initial regrowth is observable. The TEM results confirmed the presence of dislocations and twinning defects in varying concentrations correlating to the optical observations of the samples.© (1990) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

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