POLYCRYSTALLINE SILICON ROD MANUFACTURING METHOD

摘要

Switches (S1-S3) allow switching between parallel/series configuration in a circuit (16) provided between two pairs of U-shaped silicon cores (12) arranged in a bell jar (1). In the circuit (16), current is supplied from one low-frequency power source (15L) supplying a low-frequency current, or from one high-frequency power source (15H) supplying a variable-frequency, high-frequency power source is used high-frequency current having a frequency of not less than 2 kHz. The two pairs of U-shaped silicon cores (12) are connected to each other in series by closing the switch (S1) and opening the switches (S2 and S3), and when the switch (S4) is switched to the side of the high-frequency power source (15H), and electric heating of the silicon cores (12) can be performed by supplying a high-frequency current having a frequency of less than 2 kHz to the series-connected U-shaped silicon cores (12) (or polycrystalline silicon rods (11)).

主权项

1. A method for manufacturing a polycrystalline silicon rod, said method comprising
arranging a silicon core in a reactor vessel, supplying a source gas comprising trichlorosilane into the reactor vessel, and depositing polycrystalline silicon on the silicon core electrically heated using a CVD method, wherein the CVD method comprises applying a high-frequency current for heating the polycrystalline silicon rod by applying, through the polycrystalline silicon rod, current having a frequency of not less than 2 kHz from a variable-frequency, high-frequency power source, wherein the application of the high-frequency current comprises supplying a high-frequency current to the polycrystalline silicon rod whose diameter reaches a predetermined value D0 of not less than 80 mm due to the deposition on series-connected polycrystalline silicon, and during the application of the high-frequency current, the frequency of the current is selected corresponding to variation in surface temperature of the polycrystalline silicon rod to the extent that a skin depth at which the high-frequency current flows through the polycrystalline silicon rod is in the range of not less than 13.8 mm and not more than 80.0 mm, and wherein the surface temperature of the polycrystalline silicon rod is controlled in a range of not less than 900° C. and not more than 1250° C. to deposit polycrystalline silicon.