Silicon single crystal wafer for IGBT and method for manufacturing silicon single crystal wafer for IGBT

Abstract

In this silicon single crystal wafer for IGBT, COP defects and dislocation clusters are eliminated from the entire region in the radial direction of the crystal, the interstitial oxygen concentration is 8.5×1017 atoms/cm3 or less, and variation in resistivity within the wafer surface is 5% or less. This method for manufacturing a silicon single crystal wafer for IGBT includes introducing a hydrogen atom-containing substance into an atmospheric gas at a hydrogen gas equivalent partial pressure of 40 to 400 Pa, and growing a single crystal having an interstitial oxygen concentration of 8.5×1017 atoms/cm3 or less at a silicon single crystal pulling speed enabling pulling of a silicon single crystal free of grown-in defects. The pulled silicon single crystal is irradiated with neutrons so as to dope with phosphorous; or an n-type dopant is added to the silicon melt; or phosphorous is added to the silicon melt so that the phosphorous concentration in the silicon single crystal is 2.9×1013 to 2.9×1015 atoms/cm3 and a p-type dopant having a segregation coefficient smaller than that of the phosphorous is added to the silicon melt so that the concentration in the silicon single crystals is 1×1013 to 1×1015 atoms/cm3 corresponding to the segregation coefficient thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing the relationship between interstitial oxygen concentration and oxygen donor concentration after a heat treatment.

FIG. 2 is a graph showing the relationship between solidification rate and resistivity.

FIG. 3 is longitudinal cross-sectional schematic drawing of a CZ furnace used when carrying out a method for manufacturing a silicon single crystal wafer of an embodiment of the present invention.

FIG. 4 is a cross-sectional schematic drawing showing the outer peripheral portion of a silicon single crystal wafer of an embodiment of the present invention.

Claims

1. A silicon single crystal wafer for IGBT comprising a silicon single crystal grown by the Czochralski method, wherein COP defects and dislocation clusters are eliminated from the entire region in the radial direction of the crystal, the interstitial oxygen concentration is 8.5×1017 atoms/cm3 or less, and variation in resistivity within the wafer surface is 5% or less.

2. The silicon single crystal wafer for IGBT according to claim 1, wherein the silicon single crystal is grown at a pulling speed that allows pulling of silicon single crystal free of grown-in defects when grown by the Czochralski method, and is doped with phosphorous by carrying out neutron irradiation on the silicon single crystal after pulling.

3. The silicon single crystal wafer for IGBT according to claim 1, wherein the silicon single crystal is grown from a silicon melt doped with an n-type dopant at a pulling speed enabling pulling of silicon single crystal free of grown-in defects during growth by the Czochralski method.

4. The silicon single crystal wafer for IGBT according to any one of claims 1 to 3, wherein the silicon single crystal is doped with nitrogen at 1×1014 atms/cm3 to 5×1015 atoms/cm3.

5. The silicon single crystal wafer for IGBT according to claim 3, wherein the silicon single crystal is doped with phosphorous and a p-type dopant having a smaller segregation coefficient than that of phosphorous contained at a concentration of 1×1013 to 1×1015 atoms/cm3, respectively.

6. The silicon single crystal wafer for IGBT according to claim 1, wherein the LPD density in the wafer surface is 1 defect/cm2 or less, and the light etching defect density is 1×103 defects/cm2 or less.

7. The silicon single crystal wafer for IGBT according to any one of claims 1 to 3, wherein a polycrystalline silicon layer of 50 to 1000 nm is formed on the rear side.

8. A method for manufacturing a silicon single crystal wafer for IGBT obtained by growing a silicon single crystal by the Czochralski method, the method comprising: introducing a hydrogen atom-containing substance into the atmospheric gas in a CZ furnace at a hydrogen gas equivalent partial pressure of 40 to 400 Pa, growing a single crystal having an interstitial oxygen concentration of 8.5×1017 atoms/cm3 or less at a silicon single crystal pulling speed enabling pulling of a silicon single crystal free of grown-in defects, and irradiating the pulled silicon single crystal with neutrons so as to dope with phosphorous.

9. A method for manufacturing a silicon single crystal wafer for IGBT obtained by growing a silicon single crystal by the Czochralski method, the method comprising: adding an n-type dopant to a silicon melt, introducing a hydrogen atom-containing substance into the atmospheric gas in a CZ furnace at a hydrogen gas equivalent partial pressure of 40 to 400 Pa, and growing a single crystal having an interstitial oxygen concentration of 8.5×1017 atoms/cm3 or less at a silicon single crystal pulling speed enabling pulling of a silicon single crystal free of grown-in defects.

10. A method for manufacturing a silicon single crystal wafer for IGBT obtained by growing a silicon single crystal by the Czochralski method, the method comprising: adding phosphorous to a silicon melt so that the phosphorous concentration in the silicon single crystal is 2.9×1013 to 2.9×1015 atoms/cm3, adding a p-type dopant having a segregation coefficient smaller than that of the phosphorous to the silicon melt so that the concentration in the silicon single crystal is 1×1013 to 1×1015 atoms/cm3 corresponding to the segregation coefficient thereof, introducing a hydrogen atom-containing substance into the atmospheric gas in a CZ furnace at a hydrogen gas equivalent partial pressure of 40 to 400 Pa, and growing the single crystal having an interstitial oxygen concentration of 8.5×1017 atoms/cm3 or less at a silicon single crystal pulling speed enabling pulling of a silicon single crystal free of grown-in defects.

11. The method for manufacturing a silicon single crystal wafer for IGBT according to any of claims 8 to 10, wherein nitrogen is added to the silicon melt so that the nitrogen concentration in the silicon single crystal is 1×1014 to 5×1015 atoms/cm3.