Effect of Thermal Shield Structure on the Growth of 400 mm Diameter Czochralski Monocrystalline Silicon

doi:10.16553/j.cnki.issn1000-985x.2025.0133

Abstract

Abstract: Monocrystalline silicon is one of the key materials for the preparation of semiconductors. Driven by the need to reduce costs， large diameter and fast crystal pulling technology is one of the development trends in the preparation of monocrystalline silicon by Czochralski method. In this paper， a double thermal shield structure was proposed， and the effects of the double thermal shield structure on the temperature and gas flow fields， the melt-crystal interface， the growth rate of monocrystalline silicon， thermal stresses， and point defects during the growth of monocrystalline silicon were analyzed. The results demonstrate that the double thermal shield structure can guide the flow of argon gas near the solid-liquid interface， suppress vortex formation on the outer side of the thermal shield， enhance heat dissipation from the crystal， and consequently increase its growth rate， with a maximum improvement of 19.2%. At the same time， the double thermal shield structure also improves the melt-crystal interface fluctuation， and the maximum thermal stress is reduced by 4.266 MPa compared with the single thermal shield structure. Therefore， the double thermal shield structure has a better application prospect.

Key words: Czochralski monocrystalline silicon; thermal shield structure; growth rate; melt-crystal interface; thermal stress; point defect

CLC Number:

O782

AI Jincai, YANG Pingping, ZHAO Ziwei, GAO Mangmang. Effect of Thermal Shield Structure on the Growth of 400 mm Diameter Czochralski Monocrystalline Silicon[J]. Journal of Synthetic Crystals, 2026, 55(1): 68-76.

Figures/Tables 13

Fig.1 Schematic diagram of Czochralski furnace structure

Fig.2 Grid division diagram

Table 1 Physical parameters of materials

Material	Emissivity	λ_eff/（W·m^-1·K^-1）	Density/（kg·m^-3）	C_p /（J·kg^-1·K^-1）	Elastic modulus/Pa
Si crystal	0.9-0.000 26T	98.9-0.09T+2.86×10^-5T²	2 330	1 000	1.653×10¹¹
Si melt	0.3	66.5	2 332+0.48T-1.98×10^-4T²	915	—
Graphite	0.8	146.9-0.177T+1.27×10^-4T²-4.69×10^-8T³	1 750	2 100	—
Felt	0.9	0.086-7.55×10^-5T+1.3×10^-7T²	—	—	—
Quartz	0.85	4	—	—	—
Steel	0.45	15	—	—	—
Argon	—	0.01+2.5×10^-5T	—	527	—

Fig.3 Distribution of argon gas field

Fig.4 Thermal field distribution inside Cz furnace

Fig.5 Temperature distribution in melt

Fig.6 Temperature distribution of heater and crucible wall

Fig.7 Heat flux

Fig.8 Heater power

Fig.9 Axial temperature distribution near the melt-crystal interface

Fig.10 Melt-crystal interface shapes corresponding to different thermal shield structures

Fig.11 Temperature distribution inside crystal

Fig.12 Von Mises stress distribution under different thermal shield structures

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