Method for producing high quality silicon single crystal ingot and silicon single crystal wafer made thereby

Abstract

In a method for producing a high quality silicon single crystal by the Czochralski method, a lower portion of a solid-liquid interface of a single crystal growth is divided into a central part and a circumferential part, and the temperature gradient of the central part and the temperature gradient of the circumferential part are separately controlled. When a silicon melt located at a lower portion of a solid-liquid interface of a single crystal growth is divided into a central part melt and a circumferential part melt, the method controls the temperature gradient of the central part melt by directly controlling the temperature distribution of a melt and indirectly controls the temperature gradient of the circumferential part melt by controlling the temperature gradient of the single crystal, thereby effectively controlling the overall temperature distribution of the melt, thus producing a high quality single crystal ingot free of defects with a high growth velocity.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and aspects of the present invention will become apparent from the following description of embodiments with reference to the accompanying drawing in which:

FIG. 1 is a cross-sectional view of an apparatus for growing a high quality silicon single crystal ingot by the Czochralski method in accordance with an exemplary embodiment of the present invention.

FIG. 2 is a graph of defect-free pulling rates of a circumferential part and a central part of a single crystal according to the change of a gap of a heat shield in accordance with an exemplary embodiment of the present invention.

FIG. 3 is a graph of defect-free pulling rates of the circumferential part and the central part of the single crystal according to a ratio of a rotation rate (Vs) of the single crystal to a rotation rate (Vc) of a crucible in accordance with an exemplary embodiment of the present invention.

FIG. 4 is a schematic view showing that the ratio of the rotation rate (Vs) of the single crystal to the rotation rate (Vc) of the crucible influences the temperature gradients of the circumferential part and the central part of the melt and the single crystal in accordance with another exemplary embodiment of the present invention.

FIG. 5 is a graph showing the relation between the ratio (r) of the rotation rate of the single crystal to the rotation rate of the crucible and the gap (g) of the heat shield for growing a defect-free silicon crystal in accordance with an exemplary embodiment of the present invention.

Claims

1. A method for producing a high quality silicon single crystal ingot by the Czochralski method, wherein a lower portion of a solid-liquid interface of a single crystal growth is divided into a central part and a circumferential part, and the temperature gradient of a central part melt and the temperature gradient of a circumferential part melt are separately controlled.

2. The method of claim 1, wherein the temperature gradient of the circumferential part melt is controlled by controlling the temperature gradient of a single crystal.

3. The method of claim 2, wherein the temperature gradient of the single crystal is controlled by controlling a gap of a heat shield.

4. The method of claim 3, wherein the gap of the heat shield is between 10 and 50 mm.

5. The method of claim 1, wherein the temperature gradient of the central part melt is controlled by directly controlling the temperature gradient of a melt.

6. The method of claim 5, wherein the temperature gradient of the melt is controlled by controlling a ratio of a rotation rate of the single crystal to a rotation rate of a crucible.

7. The method of claim 6, wherein, assuming the rotation rate of the crucible containing the melt is Vc and the rotation rate of the silicon single crystal is Vs, the ratio of the rotation rate of the silicon single crystal to the rotation rate of the crucible satisfies the following equation: 3≦ln[Vs/Vc]≦5.

8. A method for producing a high quality silicon single crystal by the Czochralski method, wherein a ratio (r) of a rotation rate of a single crystal to a rotation rate of a crucible and a gap (g) of a heat shield satisfy the following equation:

9. The method of claim 8, wherein c in the equation is between 0.2 and 1.

10. The method of claim 8, wherein c in the equation is between 0.3 and 0.5.

11. A silicon wafer manufactured by using the high quality silicon single crystal ingot produced by the method of claim 1.