Patent ID: 8580632
Filing Date: 2013-11-12
Classification: G11C,H01L

Abstract:
1. A method of manufacturing a semiconductor device comprising the steps of: forming a first and a second nMIS channel region having a p-type conductive type by injecting p-type impurities onto a semiconductor substrate; forming a high-k film over the first and second nMIS channel regions; forming an nMIS cap film containing at least either of lanthanum and magnesium so as to cover the part over the first nMIS channel region of the high-k film and to expose the part over the second nMIS channel region of the high-k film; forming a first nMIS metal electrode over the first nMIS channel region via the high-k film and the nMIS cap film and forming a second nMIS metal electrode over the second nMIS channel region via the high-k film; and diffusing at least either of lanthanum and magnesium contained in the nMIS cap film into the part over the first nMIS channel region of the high-k film, wherein the absolute value of the second nMIS threshold voltage is greater than the absolute value of the first nMIS threshold voltage, and wherein the sum of the concentration of lanthanum atom and the concentration of magnesium atom in the second nMIS high-k film is lower than the sum of the concentration of lanthanum atom and the concentration of magnesium atom in the first nMIS high-k film.