The invention provides a method of fabricating a semiconductor device having an inversely staggered TFT capable of high-speed operation, which has few variations of the threshold. In addition, the invention provides a method of fabricating a semiconductor device with high throughput where the cost reduction is achieved with few materials.According to the invention, a semiconductor device is fabricated by forming an inversely staggered TFT which is obtained by forming a gate electrode using a highly heat-resistant material, depositing an amorphous semiconductor film, adding a catalytic element into the amorphous semiconductor film and heating the amorphous semiconductor film to form a crystalline semiconductor film, forming a layer containing a donor element or a rare gas element over the crystalline semiconductor film and heating the layer to remove the catalytic element from the crystalline semiconductor film, forming a semiconductor region by utilizing a part of the crystalline semiconductor film, forming a source electrode and a drain electrode to be electrically connected to the semiconductor region, and forming a gate wiring to be connected to the gate electrode.