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24 April 1995 Modulated photoellipsometry measurements of GaAs internal field
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A new optical instrument allowing photoellipsometric measurements is presented. Photoellipsometry (PE) is a modulation spectroscopy technique which uses ellipsometry in presence of a chopped external light excitation. PE measurements are obtained using a double modulation system, combining spectroscopic phase-modulated ellipsometry (SPME) with a laser pump beam. The experimental system described here takes advantage of the high frequency polarization of SPME (approximately equals 50 kHz). As a consequence the frequency of the pump beam can be varied up to 5 kHz. The field-induced changes in the real and imaginary parts of the bulk dielectric function can be directly measured and analyzed in terms of the pump beam power or the probe beam photon energy. Demonstration of this method is made with measurements, recorded in the band-gap E0 region (approximately equals 1.4 eV), on n-type GaAs sample. In particular, Franz-Keldish oscillations are observed with a very good sensitivity. More generally, PE measurements are compared with a theoretical model. From this preliminary study, it can be concluded that PE appears as a promising technique for semiconductor characterization.
© (1995) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Regis Vanderhaghen, S. Cueille, Bernard Drevillon, and Razvigor Ossikovski "Modulated photoellipsometry measurements of GaAs internal field", Proc. SPIE 2397, Optoelectronic Integrated Circuit Materials, Physics, and Devices, (24 April 1995);


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