Analysis of the Nucleation Kinetics of Oxide Precipitates in Czochralski Silicon

Abstract

Vacancy dependent nucleation curves were measured. They exhibit four maxima which all increase with increasing vacancy concentration. Even at 1000 °C considerable nucleation takes place for high vacancy concentrations. The analysis of nucleation based on classical nucleation theory has shown that nucleation of oxide precipitates takes place at heterogeneous nucleation sites. These sites contain oxygen atoms and vacancies and it is assumed that these sites are VO n complexes with 2<n<6. They are stable between 450°C and 700°C. As-grown silicon wafers contain a certain concentration of nucleation sites. This concentration increases or decreases during prolonged annealing and, as a result, the nucleation rate increases or decreases with annealing time, respectively. The grown-in concentration of nucleation sites can be markedly increased by appropriate rapid thermal anneal (RTA) pre-treatments. Supersaturated vacancies are assumed to be stored during RTA cooling mainly by reactions of vacancies with oxygen monomers, dimers, and trimers.

Thermoelectric performance of silicon with oxide nanoinclusions

“…Their composition, small size and spatial uniformity in the silicon matrix are consistent with oxide precipitates. Such structures are actually well known in silicon processing science, with early reports suggesting that oxide contamination can lead to the formation of small inclusions in silicon [26][27][28]. The presence of oxygen contamination in our sample is likely the result of the high-temperature in-flight treatment, which removes the hydrogen termination from the nanoparticle surface.…”

Getter Effects in Low Oxygen and High Oxygen Czochralski Silicon Wafers

“…This leads to the effect that during RTA cooling, when the Frenkel pairs recombine again, the vacancies supersaturate. In wafers with high concentration of interstitial oxygen, the excess vacancies bind to oxygen by forming VO n complexes (5). These complexes can act as nucleation centers for oxygen precipitation (6).…”

“…In wafers with high concentration of interstitial oxygen, the excess vacancies bind to oxygen by forming VO n complexes (5). These complexes can act as nucleation centers for oxygen precipitation (6). Because in the surface near region supersaturated vacancies can diffuse out, a defect denuded zone is formed here.…”

Oxygen Precipitation Properties of Nitrogen‐Doped Czochralski Silicon Single Crystals with Low Oxygen Concentration

“…where γ is the SiO 2 /Si interface energy per unit area (668 erg cm À2 ), [22] V p is the specific volume of a SiO 2 molecule in a precipitate (4.42 Â 10 À23 cm 3 ), [23] k is the Boltzmann constant, T is the absolute temperature, C O is the oxygen concentration, and C O eq is the thermal equilibrium oxygen concentration. [24] The value of R C indicates the minimum radius of thermodynamically stable oxide precipitates, that is, an oxide precipitate larger than R C can grow stably.…”

“…A schematic diagram of our model is shown in Figure . At temperatures above 1000 °C, the embryos originating from nitrogen, as proposed by Nakamura et al, are formed, and their radius is assumed to be smaller than the critical radius of an oxide precipitate ( R C ), which is determined as follows where γ is the SiO 2 /Si interface energy per unit area (668 erg cm −2 ), V p is the specific volume of a SiO 2 molecule in a precipitate (4.42 × 10 −23 cm 3 ), k is the Boltzmann constant, T is the absolute temperature, C O is the oxygen concentration, and C O eq is the thermal equilibrium oxygen concentration . The value of R C indicates the minimum radius of thermodynamically stable oxide precipitates, that is, an oxide precipitate larger than R C can grow stably .…”