(Invited) Growth of Czochralski Silicon Crystals with Ultralow Carbon Concentrations for High-Power Insulated-Gate Bipolar Transistor Devices

Nagai, Yuta; Nakagawa, Shoichi; Higasa, Mitsuo; Kashima, Katsunori

doi:10.1149/06411.0003ecst

Cited by 4 publications

(3 citation statements)

References 9 publications

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“…In the standard CZ furnace, it is difficult to prevent carbon contamination during the CZ process, because the SiO is transported by the Ar gas flow and reacts with the graphite heater and graphite susceptor. In this study, the Ar flow path that can prevent SiO from flowing through the graphite heater is improved, so as to reduce the amount of CO contamination from the graphite components [8]. Then, in order to enhance the CO evaporation from the melt, it is necessary to remove CO above the melt surface efficiently via the Ar gas flow.…”

Section: Methodsmentioning

confidence: 99%

Growth of Czochralski Silicon Crystals Having Ultralow Carbon Concentrations

Nagai¹,

Kashima²,

Nakagawa³

et al. 2015

SSP

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Reducing the carbon concentration in Czochralski (CZ) silicon crystals is crucial in order to improve the properties of high-power devices, such as on-resistance and carrier lifetime. To achieve carbon concentration reduction, it is necessary to reduce carbon monoxide (CO) contamination from the CZ furnace graphite components and to remove the carbon impurities originating from the starting material. In this study, suppressing the chemical reaction between silicon monoxide (SiO) and the graphite heater effectively reduced the CO contamination rate. Furthermore, we attempted to promote CO evaporation during the CZ process in order to remove carbon impurities from the melt. Increasing the Ar gas flow velocity above the melt surface was found to be effective in increasing the CO evaporation rate during both the melting and growth processes. The CO evaporation rate during the melting process of 8-inch CZ silicon was calculated as being of the order of 10-2μg/s. Owing to the effects of the CO evaporation, 8-inch CZ silicon crystals with carbon concentrations lower than 2.0 × 1014atoms/cm3at a solidified fraction of 0.85 were grown.

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Section: Methodsmentioning

confidence: 99%

Growth of Czochralski Silicon Crystals Having Ultralow Carbon Concentrations

Nagai¹,

Kashima²,

Nakagawa³

et al. 2015

SSP

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“…The carbon concentrations in the crystals were controlled by modifying the heater power and the argon gas flow rate during the melting stage. [19][20][21] Carbon concentrations lower than 3.0 × 10 15 atoms=cm 3 were determined using PL spectroscopy. 9,[22][23][24] The PL measurements were conducted using a 532-nm laser as an excitation source.…”

Section: Impact Of Carbon Concentration and Thermal History On Bulk L...mentioning

confidence: 99%

Crystal growth and evaluation of ultra-long carrier lifetime Czochralski silicon

Nagai¹,

Nakagawa²,

Tsubota³

et al. 2018

Jpn. J. Appl. Phys.

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Impact of the ultralow-carbon concentration of below 1 ' 10 15 atoms/cm 3 and thermal history on the bulk lifetime of phosphorus (P)-doped magnetic-field-applied Czochralski (MCZ) silicon was investigated. In order to accurately measure the long bulk lifetime, a direct-current photoconductive decay method was applied to a rectangular sample with a sectional area larger than 400 mm 2 . The measurement of an ultralong bulk lifetime of longer than 20 ms was demonstrated using the P-doped MCZ silicon with a carbon concentration of approximately 5 ' 10 14 atoms/cm 3 . Furthermore, the bulk lifetime of MCZ silicon with shorter exposure time at 300-600 °C was extremely short; we believe that the formation behavior of the carbon-related defects in the crystal growth process affect the bulk lifetime. Therefore, not only reducing the carbon concentration but also improving the thermal history at low temperature is effective for increasing the bulk lifetime of as-grown P-doped MCZ silicon.

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“…Using a well‐controlled gas flow pattern and high gas flow rate, Nagai et al. achieved an ultra‐low C level in a grown CZ‐Si crystal . Global simulation, including the simulation of the Ar gas flow and the Si melt, is generally acknowledged as an efficient method to study the transport phenomena involved in CZ‐Si crystal growth .…”

Section: Introductionmentioning

confidence: 99%

Development of carbon transport and modeling in Czochralski silicon crystal growth

Liu

Nakano

Kakimoto

2016

Crystal Research and Technology

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In Czochralski silicon (CZ-Si) crystal growth, species generated from high temperature reactions and transported by Si melt and argon (Ar) gas strongly affect the purity and quality of the grown crystals. The reduction of carbon (C) contamination in crystal is required for producing Si wafers with long carrier lifetimes. Advances in the modeling of C contamination in CZ-Si growth are reviewed on the basis of the mass transport phenomena in the Ar gas and Si domains. The generation, incorporation, and accumulation of C were investigated by the transient global simulations of heat and mass transport during the melting process of CZ-Si growth. In addition to graphite etching, two additional sources of carbon monoxide (CO) were analyzed according to their contributions to the accumulation of C in the Si melt. The effect of gas flow control on the back diffusion of the generated CO was examined via a parametric study of the furnace pressure and the Ar gas flow rate. Strategies for C content reduction are discussed on the basis of the mechanisms of C accumulation, which indicate that the final C content depends on both the growth duration as well as the flux of contaminants at the gas/melt interface.

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(Invited) Growth of Czochralski Silicon Crystals with Ultralow Carbon Concentrations for High-Power Insulated-Gate Bipolar Transistor Devices

Cited by 4 publications

References 9 publications

Growth of Czochralski Silicon Crystals Having Ultralow Carbon Concentrations

Growth of Czochralski Silicon Crystals Having Ultralow Carbon Concentrations

Crystal growth and evaluation of ultra-long carrier lifetime Czochralski silicon

Development of carbon transport and modeling in Czochralski silicon crystal growth

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