Method for growing silicon single crystals, method for manufacturing silicon wafers, and single crystal pulling apparatus

Abstract

To suppress a variation in oxygen concentration in each silicon single crystal and control the oxygen concentration by certainly fixing a convection mode.SOLUTION: A growing method of a silicon single crystal for pulling up a silicon single crystal while applying a horizontal magnetic field to a silicon melt uses a single crystal pulling-up apparatus equipped with a chamber, a crucible for storing the silicon melt, a heating unit for heating the silicon melt, a thermal shield arranged above the crucible so as to surround the silicon single crystal pulled up from the silicon melt, and an inert gas supplying unit for supplying an inert gas passing between the silicon single crystal and the thermal shield. The thermal shield is arranged so that the vertical central axis passing the center location of an opening of the thermal shield may deviate from the vertical rotation center axis of the crucible in a direction different from a direction along the application direction of the magnetic field center of the horizontal magnetic field.SELECTED DRAWING: Figure 3

Claims

1. A method for growing a silicon single crystal, comprising a single crystal pulling apparatus comprising a chamber, a crucible for storing silicon molten liquid, a heating unit for heating the silicon molten liquid, a heat shield positioned above the crucible so as to surround the silicon single crystal pulled up from the silicon molten liquid, and an inert gas supply unit for supplying an inert gas that passes between the silicon single crystal and the heat shield, wherein the silicon single crystal is pulled up while a horizontal magnetic field is applied to the silicon molten liquid, The heat shield is provided at the lower end and has a circular opening with a smaller diameter than the upper end. A method for growing a silicon single crystal, wherein when the surface of the silicon melt visible from above through the opening is divided into one side and the other side in a horizontal direction perpendicular to the direction of application by a line passing through the center of the opening and parallel to the direction of application, the smaller surface area is A and the larger surface area is B, and the thermal shield is positioned such that the vertical central axis passing through the center of the opening is offset with respect to the vertical rotational axis of the crucible in a direction different from the direction along the direction of application of the magnetic field center of the horizontal magnetic field, and in a direction having a component perpendicular to the direction of application of the horizontal magnetic field.

2. In the method for growing a silicon single crystal according to claim 1, A method for growing a silicon single crystal, wherein the heat shield is positioned such that the central axis of the heat shield is offset horizontally from the rotational axis of the crucible in a direction perpendicular to the applied heat direction.

3. The method for growing a silicon single crystal according to claim 2 is included, A method for manufacturing a silicon wafer, comprising cutting a silicon wafer from the grown silicon single crystal.

4. Chamber and, A crucible for storing molten silicon, A heating section for heating the aforementioned silicon melt, A heat shield is positioned above the crucible so as to surround the silicon single crystal that has been pulled up from the silicon melt, An inert gas supply unit that supplies an inert gas that passes between the silicon single crystal and the heat shield, The crucible comprises a magnetic field application unit for applying a horizontal magnetic field to the silicon molten liquid in the crucible, The heat shield is provided at the lower end and has a circular opening with a smaller diameter than the upper end. The heat shield is a single crystal pulling apparatus in which, when the surface of the silicon melt visible from above through the opening is divided into one side and the other side in a horizontal direction perpendicular to the direction of application by a line passing through the center of the opening and parallel to the direction of application, the smaller surface area is A and the larger surface area is B, and A / B is 0.3 or more and 0.96 or less, the vertical central axis passing through the center of the opening is offset with respect to the vertical rotational central axis of the crucible in a direction different from the direction along the direction of application of the magnetic field center of the horizontal magnetic field, and in a direction having a component perpendicular to the direction of application of the horizontal magnetic field.

5. In the single crystal pulling apparatus according to claim 4, The heat shield is positioned such that the central axis of the heat shield is offset horizontally from the rotational axis of the crucible in a direction perpendicular to the applied direction, in a single crystal pulling apparatus.

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