SEMICONDUCTOR DEVICE WITH AN INTEGRATED CMOS CIRCUIT WITH MOS TRANSISTORS HAVING SILICON-GERMANIUM (Si1-xGex) GATE ELECTRODES, AND METHOD OF MANUFACTURING SAME

摘要

Semiconductor device comprising an integrated CMOS circuit with NMOS and PMOS transistors (A, B) having semiconductor zones (23, 24, 29, 30) formed in a silicon substrate (1). At the locations of the gate zones (29, 30), the surface (3) of the substrate is provided with a layer of gate oxide (11) on which gate electrodes (16, 17) are formed. The gate electrodes (17) of the PMOS transistors (B) are formed in a layer of p-type doped polycrystalline silicon (14) and a layer of p-type doped polycrystalline silicon-germanium(13) (Si1-xGex; 0x1) sandwiched between the silicon-germanium layer and the gate oxide. The gate electrodes (16) of the NMOS transistors (A) are formed in a layer of n-type doped polycrystalline silicon (14) without germanium. The integrated CMOS circuit combines advantages of PMOS transistors having p-type doped silicon-germanium gate electrodes with advantages of NMOS transistors having n-type doped silicon gate electrodes.