SEMICONDUCTOR DEVICE AND ITS MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To enhance an operating speed of a MOS transistor by a method wherein the influences of a distribution interface resistance in a polymetal gate electrode is decreased. SOLUTION: A polymetal gate electrode 103 is formed on a silicon substrate 100 via a gate insulation film 102. The polymetal gate electrode 103 comprises: a polysilicon film 104 of a lower layer; a barrier metal layer 105 composed of a tungsten nitride film; and a metal film 106 of an upper layer composed of a tungsten film. A plug 112 is buried in a contact hole 111 formed in an interlayer insulation film 110n deposited on the polymetal gate electrode 103. A lower end part of the plug 112 is connected to a side face exposed to the contact hole 111 in the metal film 106, a side face exposed to the contact hole 111 in the barrier metal layer 105, and an upper face of the polysilicon film 104.