Investigation of grain formation and growth in nickel-induced lateral crystallization process

In this article a simple method to reveal the direction of grain growth in nickel-induced lateral crystallization (NILC) is demonstrated. This method uses 6000Å amorphous silicon film as the starting layer which is then crystallized by nickel. Then silicon dry etching is used to delineate the grains and the condition of grain growth in NILC is clearly shown. It is found that the grain growth directionality and uniformity are greatly dependent on the relative position and the shape of the nickel source origin. The optical microscope shows that the grain formation is in triangular shape. The structural condition is confirmed by an atomic force microscope which is used to scan over the grain. A mechanism of grain growth related to the movement of nickel silicide chains is proposed. Performances of n-channel metal-oxide-semiconductor transistors fabricated on different positions of the crystallized region are compared and it is found that the grain growth directionality shown after this grain-revealing method has a high correlation with the quality of the silicon in that region.