Optical absorption of precipitated oxygen in silicon at liquid helium temperature

IR studies of the oxygen and carbon precipitation processes in electron irradiated tin-doped silicon

“…Apparently, its aspect ratio is larger than that of the platelet precipitate morphology related with the 1230 cm −1 band. Returning now to the analysis of our results, we have to state that all the evidence from various studies so far lead us to correlate the 1170 cm −1 band to platelet precipitates, although the 1060 and 1080 cm −1 bands to spheroidal precipitates [72][73][74][75][76]. The band at 1040 cm −1 is just outside the frequency range (1050-1150 cm −1 ) where spheroidal precipitate bands appear [72].…”

“…The analysis shows the existence of five additional bands at around 1000, 1040, 1060, 1080 and 1170 cm −1 . Notably, the bands found by the above analysis of the Lorentzian deconvolution are physically meaningful since there is ample experimental evidence, from various measurements also at low temperature, that the bands are related with oxygen precipitate morphologies [11][12][13][71][72][73][74][75][76]. Initially, we will discuss the origin of each particular band in an attempt A mathematical way to study the behavior of a precipitate is to consider its shape as an ellipsoid with three main axes (a 1 , a 2 , a 3 ).…”

“…Initially, we will discuss the origin of each particular band in an attempt A mathematical way to study the behavior of a precipitate is to consider its shape as an ellipsoid with three main axes (a 1 , a 2 , a 3 ). The various ratios of the main axes can properly describe all the possible common shapes of precipitates that is disc, sphere, and needle [72,77,78]. This shape mainly depends on the total free energy F of the structure, that is the sum of the strain and the surface (interfacial) energy [48,79].…”

“…In addition, Sassella et al [72] assuming that the precipitate shape is modeled as a rotation ellipsoid with varying diameter/thickness ratio m (i.e. m = 1 for spheres and m >> 1 for thin discs) and applying effective medium theory (EMT) simulations showed that disc shaped precipitates gives a band around 1254 cm −1 while the spherical shaped precipitates are responsible [72] for a number of IR bands in the range of 1050-1150 cm −1 . Notably, the band at 1230 cm −1 is not present in our spectra.…”

“…IR bands at ω 1 = 1170, ω 2 = 1080, ω 3 = 1060 and ω 4 = 1040 cm −1 were related to O precipitates [72][73][74][75][76]. Before proceeding with the identification of these bands, it is necessary to discuss the absence of the 1230 cm −1 band from our spectra.…”