Grown-in defects detected by IR laser scattering tomography (LSTDs) in Czochralski-grown Si crystals were identified for the first time by transmission electron microscopy (TEM) with a special defect positioning technique. The basic structure of each LSTD was revealed to be a composite of two or three incomplete octahedral voids with a total size of 100–300 nm. The TEM images of the defects suggest the existence of walls several nanometers thick surrounding the voids. A weak oxygen signal was detected from the defect by energy dispersive X-ray spectrometry. The thin walls surrounding the voids were considered to be made of SiO x .

A practical computer simulation technique has been developed to predict oxygen precipitation behavior in Czochralski silicon wafers during various thermal processes. In this simulation, an empirical factor is introduced in the initial and boundary conditions of the Fokker-Planck equation of the oxygen precipitation in order to make up an incomplete assumption of a homogeneous nucleation process proposed by Schrems et al. ' The empirical factor is constructed as a function of heat-treatment temperature and interstitial oxygen concentration so as to describe characteristic phenomena of the precipitation nucleation processes in the 450 to 800°C range. Futhermore, an experimentally measured thermal history during a crystal growth process, which strongly influence the oxygen precipitation behavior in the subsequent thermal process, has been taken into consideration. The calculated results agree fairly well with the experimental results for a variety of thermal processes. This semi-empirical simulation technique thus provides an advantageous tool for industrial optimization of the oxygen precipitation characteristics.ABSTRACT A solid-state electrochemical cell of the type Pt/LiCoO 2 -5 mole percent (m/o) Co,,0 4 /LiCO 3 (+5 m/o LiaPO 4 + 6 m/o LiA10 2 )/Au, CO,, 0,, was composed for determining CO 2 concentration, where LiCO,, a lithium ion conductor, is an electrolyte, and LiCoO,-CoO, is used as the solid reference electrode. Electromotive force (EMF) of the cell depended logarithmically on the CO 2 partial pressure in CO,/O, gas mixtures at temperatures between 350 and 400'C. EMF reached a constant value within 1 min after the change of CO 2 partial pressure at 400°C. The sensitivity to CO 2 of this cell was not affected by coexistence of water vapor. The sensor worked stably during a test period of 30 days. The sensing mechanism of CO 2 was discussed together with an explanation to the stability of this sensor.

Present day high‐purity Czochralski(CZ)‐grown Si crystals are characterized by the bulk carrier recombination life‐time measurements. The bulk lifetime of the p‐type as‐grown Si with resistivity ∼10 Ω‐cm is found to be as high as 500 μs for a CZ‐Si crystal with false[Onormalifalse]>10 normalppma‐JEIDA and as high as ∼1 ms or even higher for a low‐oxygen CZ‐Si crystal with false[Onormalifalse]<10 normalppma‐JEIDA . The as‐grown bulk lifetime is revealed to depend not only on resistivity under the framework of the Shockley‐Read‐Hall (SRH) relation, but also on the oxygen concentration. The dominant recombination center of the as‐grown crystal is found to be an SRH‐type deep‐level center which is considered to be an oxygen‐related defect complex. The complex is quenched easily by a heat‐treatment at a temperature as low as 650°C. Effective density of a recombination center, existing after the 650°C heat‐treatment in the p‐type crystal, correlates well with the amount of oxygen precipitation generated by a subsequent two‐step heat process false[800°C normalfor 4 normalh+1000°C normalfor 16 normalhfalse] . Thus the dominant recombination center after the 650°C heat‐treatment is considered to be closely related to the oxygen precipitation nuclei toward the subsequent precipitation formation heat process.

A deep-level photoluminescence (PL), which corresponds to the D1 line (0.81 eV) at 4.2 K, is investigated at room temperature for oxygen precipitated Czochralski Si crystals in their growth directions. Analyses are made of the macroscopic and microscopic distributions of the room temperature D 1 line intensity (ID) the room temperature band-to-band PL intensity (IB), carrier lifetime (7), and precipitated oxygen concentration (A[Oi]). The relative concentration distribution of ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 169.230.243.252 Downloaded on 2015-03-20 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 169.230.243.252 Downloaded on 2015-03-20 to IP

The medium field breakdown of metal oxide semiconductor capacitor due to the Czochralski silicon crystal originated defect was studied in view of both electrical and structural analyses. By analyzing the local tunneling current which initiates the medium field breakdown, phenomenological defect sizes were calculated from the local tunneling current by assuming the local oxide thinning model. They were the defect diameter as 5 to 50 nm and the local oxide thinning as ∼25 nm. These data were confirmed by direct defect observation using high precision defect isolation procedure followed by transmission electron microscopy. Direct observation revealed that the real defect size was ∼200 nm which correlated well with other recently reported works. The real local oxide thinning,however,was not as large as phenomenological calculation. To explain the differences between phenomenological and real local oxide thinning, the poly-Si grain protrusion induced stress model was proposed.