Semiconductor device e.g. a PMOS, NMOS or CMOS transistor, a MOS capacitor or a Bi-MOS device

摘要

Semiconductor device production comprises implanting ions through an underlayer film opening to form a well, prior to forming a gate thermal oxide on the well surface. A semiconductor device production process comprises: (a) isolating an element region of a semiconductor substrate (1) using a separation oxide film (2); (b) forming an underlayer film on the element region surface; (c) forming a resist mask (7a) with an opening (7b) in a certain region on the underlayer film; (d) removing the exposed underlayer film portion; (e) forming a well (6a) by implanting first conductivity type ions (8) through the opening; (f) removing the resist mask; and (g) forming a gate dielectric film on the well surface by thermal oxidation. An Independent claim is also included for a semiconductor device produced by the above process. Preferred Features: The underlayer film comprises a single layer or multilayer structure of SiO2, SixOy with a sub stoichiometric oxygen content, SixOyNz, Si3N4, SixNy with a sub stoichiometric nitrogen content, a silicide (CoSi2, TiSi2 or WSi2) and/or TiN.