Semiconductor integrated circuit device and method for fabricating the same

Abstract

After forming a silicon oxide filmon the surface of a region A of a semiconductor substratea high dielectric constant insulating filma silicon film, a silicon oxide filmare successively deposited over the semiconductor substrateand they are patterned to leave the silicon oxide filmin regions for forming gate electrodes. Then, after fabricating silicon filmsandby using the patterned silicon oxide filmas a mask, when removing the silicon oxide filmetching is performed under the condition where the etching selectivity of the silicon oxide filmto the high dielectric constant insulating filmbecomes large, thereby leaving the high dielectric constant insulating filmalso to portions below the end of the gate electrodes (). Thus, it is possible to ensure the voltage withstanding thereof and improve the characteristics of MISFET.