Patent ID: 8575676
Filing Date: 2013-11-05
Classification: H01L

Abstract:
1. A semiconductor storage device comprising: a semiconductor substrate; an embedded insulator embedded in a trench formed in the semiconductor substrate and having an upper portion protruding above a top surface of the semiconductor substrate; a first insulating film formed on the top surface of the semiconductor substrate; a floating gate formed on the first insulating film at a side of the embedded insulator, having an upper side portion arching out above the embedded insulator; a second insulating film contacting an upper surface and a side surface of the floating gate; and a control gate disposed adjacent to the floating gate, the second insulating film being disposed between the control gate and the floating gate; the floating gate including a first conductive layer disposed on the first insulating film and a second conductive layer disposed on the first conductive layer such that a joint between the first conductive layer and the second conductive layer is more remote than a top surface of the embedded insulator from the top surface of the semiconductor substrate, the first conductive layer being laminated on the first insulating film; and the second conductive layer being wider than the first conductive layer, the second conductive layer having an overhanging side portion extending along the top surface of the semiconductor substrate beyond a side surface of the first conductive layer to overhang above the embedded insulator, the second insulating film contacting a lower surface of the overhanging side portion to intervene between the overhanging side portion and the embedded insulator.