SEMICONDUCTOR DEVICE

PROBLEM TO BE SOLVED: To provide a method by which high-resistance impurity regions (HRD or low-concentration impurity regions) are formed in source/drain regions through self-alignment way with respect to a thin-film transistor. SOLUTION: In the method, a first porous anode oxide film 107 is grown on the side surface of a gate electrode 105 at a comparatively low voltage while leaving a mask 106 on the top surface of the gate electrode 105. A gate insulating film 104' is etched by using the anode oxide film as a mask. If necessary, a second barrier type anode oxide film 108 is formed on the side surface and top surface of the gate electrode at a comparatively high voltage. The first anode oxide film is etched selectively. When performing impurity doping, the underlaid region of the gate electrode is not doped, and the regions approximating to the gate electrode become high-resistance regions 111, 112 having low impurity concentrations. The regions separating from the gate electrode become low-resistance regions 110, 113 having high impurity concentrations. COPYRIGHT: (C)2010,JPO&INPIT