The maximum phosphorus concentration that can be incorporated in a silicon crystal using the Czochralski crystal growth method was investigated. The value was found to be related to the hot-zone configuration and is about 1.11 ϫ 10 20 atom/cm 3 for 100 mm (111) crystals grown from a short tank grower with an 18 kg charge size. This doping concentration corresponds to a resistivity value of 0.00071 ⍀-cm. When the tang-end of a growing crystal reached this doping concentration, dislocations were generated at the center of the crystal about 50 mm above the solid/melt interface. The dislocations propagated down to the solid/melt interface and resulted in growing a dislocated crystal from that point on. Dislocation loop clusters were observed in the centers of the tangend crystals where the resistivity was lower than 0.00092 ⍀-cm (8.19 ϫ 10 19 atom/cm 3 ). These clusters most likely were the slip dislocation sources.

The effect of high-temperature annealing on the dissolution of crystal grown-in defects referred to as D-defects in n-type Czochralski silicon under various annealing conditions was studied. Annealing at 1200 °C for 1 h in either oxygen or nitrogen ambient causes the dissolution of the D-defects while in contrast no effect of a high-temperature annealing in hydrogen ambient on the D-defects was observed. Based upon the present analysis, D-defect dissolution during oxygen and nitrogen annealing could be attributed to vacancy undersaturation resulting from silicon interstitial injection from the silicon surface. Annealing in hydrogen ambient is hypothesized to cause vacancies at the surface sites to migrate into the silicon lattice via a Schottky defect formation mechanism.

Temperature, strength, and stress at the Dash thin neck of large diameter silicon crystals during Czochralski growth are analyzed. The combination stress from the crystal weight, the meniscus weight, and the surface tension are calculated for the initial crystal growth stage, including shoulder portion and the first 12.5 cm long of body growth. Two shoulder lengths, 2.5 and 10 cm with three diameter sizes, 200, 250, and 300 mm are calculated. A two-dimensional, axisyrnmetric heat conduction model using a commercially available software, ANSYS"." is used to calculate the temperature distribution in the crystals. The strength of the thin neck is obtained from the relationship between the upper yield strength of silicon and temperature. To maintain a dislocation-free (DH) lattice structure, the strength of the thin neck must be higher than the combination stress acting upon the thin neck. The results indicated that the neck temperature increases with the crystal diameter and decreases with the shoulder length. The minimum neck diameter to maintain a DF structure for a 200 rnrn crystal is 3.7 mm with a 2.5 cm shoulder and 3.06 mm with a 10 cm shoulder. For a 250 mm crystal, the minimum neck diameter is 4.8 mm with a 2.5 cm shoulder and 4.1 mm with a 10 cm shoulder. For a 300 mm diameter crystal, the minimum neck diameter is 6.1 mm with a 2.5 cm shoulder and 5.2 mm with a 10 cm shoulder.) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.218.248.200 Downloaded on 2015-04-12 to IP Process and Device Center, Dallas, TX 75243. Present address: National Semiconductor Corporation, Santa microscopy (STM),*." transmission electron microscopy Clara, CA 95052. (TEM),ll-l5 and x-ray diffraction (XRD),'"17 have been Present address: Hitachi, Ltd., Tokyo 185, Japan. employed t o investigate the effect o f thermal oxidation on ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.218.248.200 Downloaded on 2015-04-12 to IP

The puller thermal history effect on axial oxygen precipitation depends on the subsequent heat treatment. Two approaches can improve the axial oxygen precipitation uniformity after a two-step heat treatment (800~ h + 1050~ h). A high temperature rapid thermal process (RTP) preheating, 1200~ for 2 min in argon ambient can influence the thermal history effect by reducing the oxygen precipitation at the seed-end of the crystal in comparison to the tang-end. Low temperature preheat treatments, such as thermal donor annihilation heat treatment and polysilicon CVD processes, can increase the oxygen precipitation of the tang-end wafers much more than that of the seed-end and, therefore, also increase the uniformity of the precipitation.

The maximum antimony concentration can be incorporated in a 150 mm Si͑100͒ crystal using the Czochralski ͑CZ͒ crystal growth method was investigated. The antimony limitation was found to be about 5.96 ϫ 10 18 atom/cm 3 ͑0.0084 ⍀ cm͒ using a charge size of 45,000 g. It was limited by the occurrence of constitutional supercooling in the center of the crystal. A ripple or instability in the solid/melt interface was observed in the center of the crystal at the onset of constitutional supercooling. Cellular growth structure was observed when the ripple reached a critical magnitude of 0.027 cm in the growth direction. When cellular growth occurred, cellular structure formed and dislocation networks were found in the boundaries of the cells. The melt temperature gradient at the solid/melt interface was calculated to be about 9.86°C/cm.