Patent ID: 7452774

Claim:
A method of manufacturing a semiconductor device having a first region and a second region, the method comprising: forming a first oxide film on a substrate in the first region; forming a second oxide film on the substrate in the second region; forming a first conductive layer over a portion of the substrate that includes at least the first oxide film and the second oxide film; introducing impurities into the first conductive layer; forming a first insulating layer over the first conductive layer; removing at least a portion of the first insulating layer over the second region; forming a second conductive layer over at least a portion of the substrate such that the first and second conductive layers are separated by the first insulating layer in the first region and the first and second conductive layers are at least partially in contact with each other over their cross-sections in the second region; and introducing impurities into the second conductive layer such that the second conductive layer has a conductivity that is higher than the first conductive layer in the first region, and such that the first and second conductive layers have substantially the same conductivity in the second region.