Patent ID: 8878282
Filing Date: 2014-11-04
Classification: H01L

Abstract:
1. A nonvolatile semiconductor storage device including memory cells, the memory cells comprising: a semiconductor substrate; a tunnel insulating film formed above the semiconductor substrate; a charge storage layer formed above the tunnel insulating film; an insulating film formed above the charge storage layer; and a gate electrode formed above the insulating film, the gate electrode including at least a first gate electrode layer and a second gate electrode layer formed above the first gate electrode layer, the first gate electrode layer is in contact with the insulating film, the second gate electrode layer is formed above the first gate electrode layer and mainly consists of a material different from that of the first gate electrode layer, and the second gate electrode layer has a dimension smaller in the direction of gate length than the first gate electrode layer, and a thickness of the second gate electrode layer being larger than a thickness of the first gate electrode layer, and the first gate electrode layer includes tantalum, and the first gate electrode layer includes oxygen at its edges.