A method of fabricating a hybrid orientation substrate is described. A silicon substrate with a first orientation having a silicon layer with a second orientation directly thereon is provided, and then a stress layer is formed on the silicon layer. A trench is formed between a first portion and a second portion of the silicon layer through the stress layer and into the substrate. The first portion of the silicon layer is amorphized. A SPE process is performed to recrystallize the amorphized first portion of the silicon layer to be a recrystallized layer with the first orientation. An annealing process is performed at a temperature lower than 1200° C. to convert a surface layer of the second portion of the silicon layer to a strained layer. The trench is filled with an insulating material after the SPE process or the annealing process, and the stress layer is removed.