METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for manufacturing a semiconductor device is provided to increase a hot carrier lifetime caused by nitrogen ions, by injecting nitrogen ions into a LDD(Lightly Doped Drain) region and a source/drain region of the device having a thick gate insulating layer. CONSTITUTION: Gate electrodes(24,24a) having gate insulating layers of different thickness are formed on a semiconductor substrate(21). A low density impure ions are injected into the substrate on both sides of the gate electrodes. Nitrogen ions are injected into a portion injected with the low density impure ions, the portion belonging to the region in which a relatively thick gate insulating layer as compared with the gate insulating layers is formed. A sidewall spacer is formed on both sides of the gate electrodes. Source/drain impurity ions are injected into the substrate.