Crystalline silicon ingot and method of fabricating the same

A method for fabricating a crystalline silicon ingot, comprising:

• forming a silicon melt in a crucible defining a vertical direction;
• controlling at least one thermal control parameter of said silicon melt such that multiple silicon crystal grains in said silicon melt nucleate on an inner wall of a bottom of said crucible and grow along said vertical direction;
• and
• controlling said at least one thermal control parameter continually until entirety of said silicon melt solidifies to become said crystalline silicon ingot,
• wherein said crystalline silicon ingot has a bottom with a silicon crystal grain having a first average crystal grain size of less than about 12 mm,
• wherein said inner wall of said bottom of said crucible has multiple protrusions performed by spraying coating slurry with a spray coating pressure from 40 psi to 60 psi and a spraying coating temperature from 40 degree Celsius to 60 degree Celsius, said protrusions having a roughness ranging from 300 micrometers to 1000 micrometers such that said inner wall of said bottom provides multiple nucleation sites for silicon crystal grains.