Influence of annealing during growth on defect formation in Czochralski silicon

Nakanishi, Hideo; Kohda, Hiroki; Hoshikawa, Keigo

doi:10.1016/0022-0248(83)90282-8

Cited by 16 publications

(11 citation statements)

References 7 publications

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“…The relative absence of detectable defects in approximately 10 -7 cm ~ of Quench material after the 1050~ treatment is consistent with the observation by Nakanishi et al (6) that densities after such annealing in Quench material can be down from those in Ramp/Shield material by several orders of magnitude. The relative absence of detectable defects in approximately 10 -7 cm ~ of Quench material after the 1050~ treatment is consistent with the observation by Nakanishi et al (6) that densities after such annealing in Quench material can be down from those in Ramp/Shield material by several orders of magnitude.…”

Section: Fig 2 O: Defects In Ramp Crystals After 775~ Wafer Heattresupporting

confidence: 90%

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The Effects of Thermal History during Growth on O Precipitation in Czochralski Silicon

Fraundorf

Craven

et al. 1985

J. Electrochem. Soc.

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High oxygen wafers from 100 mm diam Si crystals grown by the Czochralski process, but subjected to three different thermal histories in an experimental puller, were examined by Wright etching, transmission electron microscopy, and Fourier transform infrared spectroscopy after wafer heat-treatments at 775 ~ 1050 ~ 775 ~ + 1050 ~ and 1320 ~ + 775 ~ + 1050~ Only wafers near the seed end of each ingot were used, thus minimizing differences in parameters other than thermal history. The observations show that defect morphology and O precipitate number density (not total O precipitation) after the one-and two-step heat-treatments depend on thermal history in the puller. In particular, 775~ heated wafers which spent less than an hour in the puller below 1000~ show number densities down by more than a factor of 100 from those which spent longer. On the other hand, the observations indicate that effects of puller thermal history are erased with a short 1320~ anneal, or typical VLSI multistep pretreatments which enhance bulk oxygen precipitation. In addition, the results suggest two possible complications for simple models of oxygen precipitation. These are that 500~ annealing can be much more effective than 775~ annealing for nucleating oxygen precipitates, contrary to model predictions, and that critical sizes for precipitate dissolution at 1050~ can be much larger than predicted by classical calculations.) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.255.6.125 Downloaded on 2015-06-05 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.255.6.125 Downloaded on 2015-06-05 to IP

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Section: Fig 2 O: Defects In Ramp Crystals After 775~ Wafer Heattresupporting

confidence: 90%

“…Independently, Nakanishi et al (6) have demonstrated that defect density after a 1050~ wafer heat-treatment can be decreased, and the defect radial distribution modified, by rapid cooling of a 3 in. diam ingot after crystallization.…”

mentioning

confidence: 99%

The Effects of Thermal History during Growth on O Precipitation in Czochralski Silicon

Fraundorf

Craven

et al. 1985

J. Electrochem. Soc.

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“…The investigated 750 mm‐long ingot was pulled with a relatively slow speed of 36 mm h −1 , leading to a cooling rate of about 100 K h −1 at temperatures above 1300 °C. [ 20 ] However, in current Cz‐Si manufacturing (especially for photovoltaics) the pulling rate is much higher (≥60 mm h −1 ), [ 18,21 ] leading to high cooling rates (≫100 K h −1 ) at high temperatures where the temperature–time profile flattens out as room temperature is approached. [ 20,21 ] Nielsen et al [ 5 ] recently even introduced active cooling near the melt/crystal interface in industrial ingot manufacturing to increase throughput.…”

Section: Introductionmentioning

confidence: 99%

Comprehensive Model for Charge Carrier Recombination in Czochralski‐Grown Silicon Due to Oxygen Precipitation in Industrial Solar Cell Manufacturing

et al. 2022

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Oxygen precipitates are among the most detrimental oxygen‐related silicon bulk defects formed during solar cell manufacturing. These defects are formed only during high‐temperature processes, impeding an identification of prone materials during incoming inspection. Moreover, the prediction of oxygen‐precipitate‐related bulk charge carrier recombination currently requires advanced numerical simulation. This work presents an easily implementable model to predict the bulk carrier lifetime limit, using the temperature–time profile of a high‐temperature process as well as the material properties as the input data. In addition to published analytical descriptions of oxygen precipitation, an empirical description of the retarded growth of small precipitates is included. Furthermore, the time‐lag in nucleation is explicitly considered, which is, to our knowledge, not implemented in oxygen precipitation modeling so far. The calibration of the two free parameters of the model is achieved using the experimental data of 19 different thermal process combinations performed using a single material. This results in a good agreement not only for the material used for calibration but also for other silicon materials. A validation based on passivated emitter and rear cells as well as on test structures confirms the ability of the model to predict bulk carrier lifetimes after solar cell processing.

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“…[12] The seed end will stay in the cold zone of the Cz-Si pulling process for a prolonged time, and the thermal history will thereby vary as a function of crystal height with deviations in impurity distribution. A study by Nakanishi et al [13] showed that if different cooling profiles are used for two crystals, the fastest cooling crystal will have less supersaturated oxygen precipitates after 12 h heat treatment. When the crystal grows and solidifies, the oxygen out-diffuses and there is a drastic decrease in oxygen concentration in Cz material near the periphery region.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Pull Speed and Heat Treatment on Thermal Donors in Czhocralski Silicon

Olsen

Mehl

Stalheim

et al. 2021

Physica Status Solidi (a)

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In silicon crystals manufactured by the Czochralski method, oxygen is incorporated as a contaminant originating primarily from dissolution of the quartz crucible used to contain the molten silicon feedstock. The oxygen can be found either as interstitials, agglomerates, or as oxide particles. Particular kinds of agglomerates are known to lead to the formation of thermal donors—electronic states in the bandgap of the silicon base material. These can act as sites for recombination of excited charge carriers and are called thermal donors due to their ability to inject two electrons into the conduction band of silicon by thermal excitation, leading to enhanced electrical conductivity. Neither of these features are desirable in Cz‐Si manufacture. Herein, the behavior of thermal donors as a function of the pull speed, and the position in the ingot, is investigated. Thermal treatment is provided, first for the formation of thermal donors and then for their removal. The aim is to investigate methods for minimalizing their incorporation in the crystal in the first place and then how they can be removed. Hyperspectral imaging and spectroscopy combined with Fourier‐transform infrared spectroscopy are used.

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Influence of annealing during growth on defect formation in Czochralski silicon

Cited by 16 publications

References 7 publications

The Effects of Thermal History during Growth on O Precipitation in Czochralski Silicon

The Effects of Thermal History during Growth on O Precipitation in Czochralski Silicon

Comprehensive Model for Charge Carrier Recombination in Czochralski‐Grown Silicon Due to Oxygen Precipitation in Industrial Solar Cell Manufacturing

The Effect of Pull Speed and Heat Treatment on Thermal Donors in Czhocralski Silicon

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