Process for production of silicon single crystal, and highly doped n-type semiconductor substrate

Abstract

After adding phosphorus (P) and germanium (Ge) into a silicon melt or adding phosphorus into a silicon/germanium melt, a silicon monocrystal is grown from the silicon melt by a Czochralski method, where a phosphorus concentration [P](atoms/cm) in the silicon melt, a Ge concentration in the silicon monocrystal, an average temperature gradient G(K/mm) and a pull speed V (mm/min) are controlled to satisfy a formula (1) as follows, a phosphorus concentration [P](atoms/cm) and the Ge concentration [Ge](atoms/cm3) in the silicon monocrystal satisfy a relationship according to a formula (2) as follows while growing the silicon monocrystal, where d(Å) represents a lattice constant of silicon, r(Å) represents a covalent radius of silicon, r(Å) represents a covalent radius of phosphorus, and r(Å) represents a covalent radius of Ge: