Precipitation of oxygen in silicon

Abstract

At high temperatures (1200 °C) the precipitation of oxygen in bulk dislocation-free Czochralski silicon is inhibited by the absence of nucleation centers. A substantial supersaturation corresponding to a temperature drop of about 80 °C below the equilibrium saturation temperature is necessary for nucleation to occur. However, following a preliminary low-temperature treatment (700 °C) precipitation occurs at a substantially smaller undercooling. This suggests that precipitation in crystals without a prior low-temperature treatment occurs by homogeneous nucleation in the crystalline phase, in the absence of structural defects. Using classical nucleation theory the surface free energy of the precipitate is calculated to be about 100 erg/cm2 and the critical nucleus contains about 200 oxygen atoms.

Denuded Zones in Czochralski Silicon Wafers

“…There are several mechanisms proposed by different authors for oxygen precipitate nucleation process such as the homogeneous nucleation mechanism (Freeland et al, 1977;Oosaka and Wada, 1979;Takaoka, Oosaka and Inoue, 1979), the heterogeneous nucleation mechanism (Ravi, 1975; de Kock and Van de Wijgert, 1979;Chikawa and Shirai, 1979;Shimura, Tsutomu and Kawamura, 1980a;Series, Barraclough and Bardslau, 1981;etc. ), the combination of homogeneous and heterogeneous mechanisms (Batavin, 1970), as well as the homogeneous nucleation involving the reaction of oxygen atoms with vacancy complexes (Hu, 1981).…”

Intrinsic point defect behavior in silicon crystals during growth from the melt: A model derived from experimental results

“…Oxygen precipitation in such wafers can be best described by the homogeneous nucleation theory [27]. However, the AOP phenomenon introduced here is found in wafers cut from a crystal that was detached from the melt and cooled rapidly.…”

Point Defects in Silicon Melt Growth from the Experimental Results

“…(17) The oxygen precipitation phenomenon in devices process is generally spoken using the wafer cut from the crystal which has a long thermal history in order to grow the end cone part. It is believed that the oxygen precipitation occurred in the wafer is followed by so called the homogeneous nucleation theory (23). However, the AOP phenomenon introduced here is about the wafer cut from the crystal which is detached from the melt and cooled rapidly, in other word without so called the thermal history.…”