| 摘要 |
PURPOSE:To obtain gate electrodes having no dispersion with a good accuracy by a method wherein the gate region and the polycrystalline Si of the region in its neighborhood are not doped with an impurity or doped just in a small amount, and then the thick polycrystalline Si in the wiring region is made to contain a high concentration impurity, which are etched for the same time. CONSTITUTION:A thick field SiO2 film 2 is provided in the neighborhood of a P type Si substrate 1, a thin gate SiO2 film 3 being adhered to the region surrounded with it, and a polycrystalline Si layer 4 then being deposited over the entire surface including it. Next, the region other than the gate region and its neighborhood is covered with a silica film 5, and the exposed part of the layer 4 is thinned by etching, and the impurity concentration in the layer 4 at the region other than the gate region and its neighborhood is increased by the diffusion of the impurity in the film 5 on heat treatment. Thereafter, the film 5 is removed, photo resist films 6 of required shapes are provided in the thick and thin parts, respectively. The exposed part of the layer 4 is removed by etching, thereby the gate electrode 7 made of the layer 4 is left on the film 3, and a wiring 8 on the film 2. |
