Patent ID: 8436415
Filing Date: 2013-05-07
Classification: H01L

Abstract:
1. A nonvolatile semiconductor memory device, comprising: a memory string having a plurality of electrically rewritable memory cells connected in series; and a first select transistor connected to one end of the memory string and configured to be conductive when the memory string is selected, the memory string comprising: a first semiconductor layer including a columnar portion extending in a stacking direction on a substrate and functioning as a channel of the memory cells; a first charge storage layer surrounding the columnar portion and retaining data of the memory cells by storing a charge; and a plurality of first conductive layers stacked on the substrate so as to surround the first charge storage layer and functioning as control electrodes of the memory cells, the first select transistor comprising: a second semiconductor layer in contact with an upper surface of the columnar portion and extending in the stacking direction, and functioning as a channel of the first select transistor; a second charge storage layer surrounding the second semiconductor layer and changing a threshold voltage of the first select transistor by storing a charge; and a second conductive layer deposited above the first conductive layer to surround the second charge storage layer and functioning as a control electrode of the first select transistor, the second charge storage layer being formed from a layer downward of the second conductive layer to an upper end vicinity of the second conductive layer, and being not formed in a layer upward of the upper end vicinity.