Growth technique for silicon-on-ceramic

摘要

The present invention is an improvement to the method of growing silicon films on a substrate by bringing the substrate in contact with molten silicon. The improved growth technique may be classified as an asymmetric mode of growth of silicon on the substrate and is characterized by the substrate being maintained at a higher temperature than the solidification of silicon in the area of the substrate where the silicon layer growth is taking place, that is in the area of the liquid-solid interface. The higher temperature of the substrate causes the liquid-solid interface to be tilted to be nearly parallel to the substrate surface but inclined at a reentrant angle, so that the leading edge of the crystallization front is away from the substrate. This provides several advantages including increased growth speed, a nonhomogeneous doping of the silicon layer, that is an impurity concentration gradient and results in a high-low junction at the back surface and gives the back surface field effect.