Effect of Grown-In Defects on the Structure of Oxygen Precipitates in Cz-Si Crystals with Different Diameter

Abstract

IR-spectroscopy with computer analysis of the shape of the Si-O absorption band, electron microscopy, X-rays diffraction and measurements of unsteady photoconductivity timedecay under band-to band excitation were used to investigate the influence of defects in different diameter (40 – 300 mm) Si ingots on the oxygen precipitation due to two-stage annealing (750 оС + 1050 оС). It is shown that large size Cz-Si ingots have a relatively low concentration of electrically active micro-defects, containing small (0.06 – 0.1 μm) dislocation loops. During thermal treatments this leads to the formation of a low stressed oxide phase (SiO2) with an enhanced thermo-stability. The precipitates in small size ingots, however, contain distorted 4-fold rings of SiO4 tetrahedra.

Oxygen Precipitation Related Stress-Modified Crack Propagation in High Growth Rate Czochralski Silicon Wafers

“…These absorption bands indicate the presence of oxygen precipitates with different stoichiometry, shape and vibration modes at Location 4. 13,[16][17][18][19][20][21][22] Table I lists the various FTIR peak positions and the corresponding Si-O defect types that are commonly observed in CZ silicon ingots. The large peaks at the wavenumbers from 1180 to 1260 cm −1 suggest the presence of high density of oxygen precipitates.…”

Stimulated oxygen impurity gettering under ultra-shallow junction formation in silicon

“…where σ (= 0.43 J m −2 for SiO 2 ) is the specific energy of the interface of the SiO x precipitate with the Si matrix [21], (= 2.25 × 10 −29 m 3 for SiO 2 ) is the volume per oxygen atom in the silicon oxide phase [22], k is the Boltzmann constant, T is the temperature, C, V, and I are the concentrations of interstitial oxygen, vacancies, and Si self-interstitials, respectively, and C eq , V eq , and I eq are their equilibrium concentrations, respectively [9,23]. β and γ are the number of vacancies and interstitials, respectively, absorbed in the precipitate per precipitated oxygen atom.…”