SEMICONDUCTOR DEVICE AND MANUFACTURING METHOD THEREOF

摘要

PURPOSE: A semiconductor device is provided to prevent a gate oxide layer from deteriorated by plasma etching induced damage in a selective etching process of a polycrystalline silicon layer for a gate electrode. CONSTITUTION: A silicon substrate(100) has an active region(110) and a dummy active region(130). An ion implantation layer(140) is formed on the silicon substrate in the dummy active region to control oxidation of the silicon substrate in the dummy active region. The first gate oxide layer(400) of the first thickness is formed on the silicon substrate in the active region. The second gate oxide layer(410) of the second thickness thinner than the first thickness is formed on the silicon substrate in the dummy active region. The first gate(500) is formed in a predetermined region of the first gate oxide layer.