Provided are a method of forming a single crystalline silicon layer, a structure including the same, and method of fabricating a thin film transistor (“TFT”) using the same. The method of forming the single crystalline silicon layer includes forming a silicon nitride layer on a substrate, forming an insulating layer on the silicon nitride layer, forming a hole in the insulating layer to a predetermined dimension, depositing a first silicon layer on an exposed bottom of the hole using a selective deposition process, depositing a second silicon layer on the insulating layer and the first silicon layer formed in the hole, and crystallizing the second silicon layer using a thermal process. In this method, a high-quality single crystalline silicon layer can be obtained.