Patent ID: 8901633
Filing Date: 2014-12-02
Classification: G11C,H01L

Abstract:
1. A semiconductor storage device comprising: a first insulating film formed on a substrate and functioning as a FN (Fowler-Nordheim) tunnel film; a first floating gate formed on the first insulating film; an inter-floating-gate insulating layer formed on the first floating gate and functioning as a FN tunnel film; a second floating gate formed on the inter-floating-gate insulating layer; a second insulating film formed on the second floating gate; and a control gate formed on the second insulating film, wherein the inter-floating-gate insulating layer includes a third insulating film and a fourth insulating film which has a charge trap property that are stacked, wherein the fourth insulating film is formed on the third insulating film, and wherein the third insulating film has a lower charge trap property than the charge trap property of the fourth insulating film.