SiOx precipitate composition in Si, revisited: Discussion closed?

Abstract

The composition SiOx of oxide precipitates in Si has been discussed for the past thirty years with experimentally estimated x ‐values ranging between 1 and 2. It is shown that this spread of x ‐values can be explained by calculating the average composition taking into account temperature and anneal time dependent size and shape of the precipitates and the limitations and probing volumes of the various characterization techniques. Hereby it is assumed that the oxygen‐rich (SiO2?) core of the precipitates is surrounded by a 2 nm thin SiO layer as revealed by recent electron energy loss spectroscopy analyses. For plate‐like precipitates thinner than and for octahedral precipitates smaller than 6 nm, x ≈ 1. For larger precipitates, the central part of the precipitate consists of SiOx with x close to 2 and the precipitate has an average x between 1 and 1.3 for plate‐like and up to 1.9 for octahedral precipitates. The predicted x ‐values for different precipitate sizes and morphologies, are compared with published experimental data. SiOx precipitate nucleation and initial growth should be simulated assuming x = 1 and Fourier transform infrared spectra of precipitates assuming a mixture of SiO2 and amorphous Si. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)