METHOD FOR PRODUCING SINGLE CRYSTAL, AND METHOD FOR PRODUCING SILICON WAFER

• US 20160102418A1
• Filed: 04/15/2014
• Published: 04/14/2016
• Est. Priority Date: 04/24/2013
• Status: Active Grant

• Current Assignee: Sumco Techxiv Corporation (Sumco Corporation)
• Original Assignee: Sumco Techxiv Corporation (Sumco Corporation)
• Inventors: NARUSHIMA, Yasuhito, KUBOTA, Toshimichi, OGAWA, Fukuo, UTO, Masayuki
• Granted Patent: US 10,233,562 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B28D 5/0011 with preliminary treatment, e.g. weakening by scoring
• CPC Class Codes: C30B 15/04 adding doping materials, e.g. for n-p-junction
• CPC Class Codes: C30B 15/14 Heating of the melt or the crystallised materials
• CPC Class Codes: C30B 15/20 Controlling or regulating controlling or regulating in general G05
• CPC Class Codes: C30B 15/206 the thermal history of growing the ingot
• CPC Class Codes: C30B 25/10 Heating of the reaction chamber or the substrate
• CPC Class Codes: C30B 25/186 being specially pre-treated by, e.g. chemical or physical means
• CPC Class Codes: C30B 29/06 Silicon
• CPC Class Codes: C30B 33/00 After-treatment of single crystals or homogeneous polycrystalline material with defined structure C30B31/00 takes precedence

Abstract

A manufacturing method of a single crystal uses a single-crystal pull-up apparatus includes: adding the red phosphorus to the silicon melt so that a resistivity of the single crystal falls in a range from 0.7 mΩ·cm to 0.9 mΩ·cm; subjecting an evaluation silicon wafer obtained from the single crystal to a heat treatment in which the evaluation silicon wafer is heated at 1200 degrees C. for 30 seconds in a hydrogen atmosphere; and pull-up the single crystal while appropriately controlling a period for a temperature of the single crystal to be in a range of 570±70 degrees C. so that the number of pits generated on the evaluation silicon wafer becomes 0.1/cm² or less.

Claims

1. A manufacturing method of a single crystal using a single-crystal pull-up apparatus comprising a chamber, a crucible disposed in the chamber and adapted to receive a dopant-added melt in which red phosphorus is added to a silicon melt, and a pull-up portion that is configured to pull up a seed crystal after the seed crystal is brought into contact with the dopant-added melt, the method comprising:

adding the red phosphorus to the silicon melt so that a resistivity of the single crystal falls in a range from 0.7 mΩ

·

cm to 0.9 m∩

·

cm;

subjecting an evaluation silicon wafer obtained from the single crystal to a heat treatment in which the evaluation silicon wafer is heated at 1200 degrees C. for 30 seconds in a hydrogen atmosphere; and

pull-up the single crystal while appropriately controlling a period for a temperature of the single crystal to be in a range of 570±

70 degrees C. so that the number of pits generated on the evaluation silicon wafer becomes 0.1/cm² or less.

2. The manufacturing method of the single crystal according to claim 1, further comprising:

disposing a cooler above the crucible in the chamber; and

cooling the single crystal with the cooler in a straight-body-formation step for forming a straight body of the single crystal, thereby appropriately controlling the period for the temperature of the single crystal to be in the range of 570±

70 degrees C.

3. The manufacturing method of the single crystal according to claim 1, further comprising:

disposing a heater above the crucible in the chamber;

heating the single crystal with the heater in a straight-body-formation step for forming a straight body of the single crystal to restrain a decrease in the temperature of the single crystal; and

cooling the single crystal after a tail-formation step for forming a tail of the single crystal, thereby appropriately controlling the period for the temperature of the single crystal to be in the range of 570±

70 degrees C.

4. The manufacturing method of the single crystal according to claim 1, wherein

the single crystal is pulled up so that the period for the temperature of at least a part of the single crystal to be in the range of 570±

70 degrees C. is in a range from 20 to 200 minutes.

6. A manufacturing method of an epitaxial silicon wafer, comprising:

a first step of cutting the silicon wafer from the single crystal manufactured through the manufacturing method of a single crystal according to claim 1;

a second step of heating the silicon wafer cut out in the first step in a hydrogen atmosphere; and

a third step of forming an epitaxial film on the silicon wafer after the second step to manufacture the epitaxial silicon wafer.

5. A manufacturing method of a silicon wafer using a single crystal obtained using a single-crystal pull-up apparatus comprising a chamber, a crucible disposed in the chamber and adapted to receive a dopant-added melt in which red phosphorus is added to a silicon melt, and a pull-up portion that is configured to pull up a seed crystal after the seed crystal is brought into contact with the dopant-added melt, the method comprising:

adding the red phosphorus to the silicon melt so that a resistivity of the single crystal falls in a range from 0.7 mΩ

·

cm to 0.9 mΩ

·

cm;

pull-up the single crystal; and

cutting the silicon wafer from a portion of the single crystal, a temperature of the portion being 570±

70 degrees C. for 20 to 200 minutes when the single crystal is pulled up.

7. A single crystal manufactured using a silicon melt added with red phosphorus so that a resistivity of the silicon melt is in a range from 0.7 m∩

·

cm to 0.9 m∩

·

cm, the single crystal comprising;

a straight body comprising a crystal region in which the number of pits generated on a silicon wafer cut out from the single crystal is 0.1/cm² or less after applying a heat treatment for heating the silicon wafer at 1200 degrees C. for 30 seconds in a hydrogen atmosphere.

8. An epitaxial silicon wafer comprising:

a silicon wafer cut out from the single crystal according to claim 7; and

an epitaxial film formed on the silicon wafer.