| 摘要 |
PURPOSE:To intensify an electric field in the side surfaces of a gate electrode and to inhibit relaxation of a drain electric field and the generation of a depletion layer in a low-concentration impurity layer constituting a drain region by a method wherein a dielectric high in permittivity is used for an insulating film which is provided on the sidewalls of the gate electrode of an LDD transistor. CONSTITUTION:A silicon oxide film 12 is formed on part of the surface of a P-type silicon semiconductor substrate 11, a conductor, such as an impurity, is introduced in the film 12 and a gate electrode 13, which is brought into a low resistance state and consists of a polysilicon film, is formed. A silicon oxide film 14 is formed on the surface of the substrate and on the surface of the substrate 13. An insulating film 15 consisting of a material of a dielectric constant higher than that of at least silicon oxide, such as tantalum oxaide, is formed on a pair of opposed sidewalls of the electrode 13 via the film 14. In an LDD transistor, as the film 15 consisting of the high-dielectric constant material exists on the sidewalls of the electrode 13, the intensity of electric field from the side surface of the electrode toward 13 the substrate becomes very strong when a prescribed voltage of a positive polarity is applied to the electrode 13.
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