Methods for forming a silicon substrate with reduced grown-in nuclei for epitaxial defects and methods for forming an epitaxial wafer

A method for forming a silicon substrate with reduced grown-in nuclei for epitaxial defects, the method comprising:

• adding an initial charge of polycrystalline silicon to a crucible disposed in an ingot puller apparatus;
• heating the crucible comprising the initial charge of polycrystalline silicon to cause a silicon melt to form in the crucible;
• adding a single dopant to the crucible, the single dopant being boron, boron being added to the crucible to prepare a doped silicon melt having a boron concentration of at least 3.8×1018 atoms/cm3;
• contacting a silicon seed crystal with the doped silicon melt;
• withdrawing the silicon seed crystal to grow a single crystal silicon ingot, the ingot having a constant diameter portion;
• controlling (i) a growth velocity, v, and/or (ii) an axial temperature gradient, G, during the growth of a segment of the constant diameter portion of the ingot having a boron concentration of less than 8.0×1018 atoms/cm3, the ratio of v/G being controlled such that the ratio v/G is less than a critical v/G and interstitials are the dominant intrinsic point defect in the segment;
• pulling the segment through a hotzone of the ingot puller apparatus, the segment of the constant diameter portion of the ingot being cooled from its solidification temperature to 950° C. or less as the segment is pulled through the hotzone, wherein the dwell time the segment of the constant diameter portion of the ingot is in the temperature range from 1150° C. to 950° C. is less than 160 minutes;
• and
• slicing the substrate from the single crystal silicon ingot.