Semiconductor device including a transistor with a gate electrode having a taper portion

A method for manufacturing a semiconductor device having a circuit made up by a TFT (Thin Film Transistor) having GOLD (Gate-Drain Overlapped LDD) structure, which an LDD region overlaps which a portion of a gate electrode, wherein the formation of a concentration depth profile peak of hydrogen in a semiconductor film is avoided to thereby improve the electrical characteristics of the TFT. The use of the semiconductor film manufactured in this manner allows manufacturing of a semiconductor device with good electrical characteristics only by hydrogenating treatment even when the activation of impurity elements does not carried out.