Patent ID: 9117848
Filing Date: 2015-08-25
Classification: H01L

Abstract:
1. A nonvolatile semiconductor memory device comprising: a first structure stacked in order of a first oxide layer, a semiconductor layer and a second oxide layer in a first direction, the first structure extending in a second direction crossing the first direction; and a second structure stacked in order of a gate oxide layer, a charge storage layer, a block insulating layer and a control gate electrode in a third direction crossing the first and second directions on a surface of the semiconductor layer, the third direction crossing the surface of the semiconductor layer, wherein the surface of the semiconductor layer has a concave curve, and is located inside surfaces of the first and second oxide layers, the concave curve is provided in a cross sectional plane in the first and third directions, a surface of the charge storage layer beside the gate oxide layer has a convex curve, and the semiconductor layer has tapered portions extending in the third direction in portions in which the semiconductor layer is in contact with the first and second oxide layers.