Method for producing silicon single crystal

A production method of a monocrystalline silicon according to a Czochralski process with use of a monocrystal pull-up apparatus, the apparatus comprising:

• a chamber;
• a crucible located in the chamber;
• a heater configured to heat the crucible to produce a dopant-added melt comprising a silicon melt and a dopant added to the silicon melt;
• and
• a pull-up unit configured to pull up a seed crystal after bringing the seed crystal into contact with the dopant-added melt,
• wherein the heater comprises an upper heater configured to heat an upper side surface of the crucible and a lower heater configured to heat a lower side surface of the crucible,
• the method comprising:
• forming a neck of the monocrystalline silicon;
• forming a shoulder of the monocrystalline silicon;
• and
• forming a straight body of the monocrystalline silicon,
• wherein:
• in the forming of the neck, the seed crystal is brought into contact with the dopant-added melt while the crucible is heated such that a heating ratio, which is calculated by dividing a volume of heat from the lower heater by a volume of heat from the upper heater, becomes 1.5 or less, and
• in the forming of the shoulder, the shoulder is formed by heating the crucible such that the heating ratio increases from a predetermined value of 1 or more.