Nonvolatile semiconductor storage device and method of manufacture thereof
AssigneeKabushiki Kaisha Toshiba
InventorToshitake Yaegashi
Life of this patent
Estimating the term…
Abstract
A nonvolatile semiconductor storage device including a number of memory cells formed on a semiconductor substrate, each of the memory cells has a tunnel insulating film, a charge storage layer, a block insulating film, and a gate electrode which are formed in sequence on the substrate. The gate electrode is structured such that at least first and second gate electrode layers are stacked. The dimension in the direction of gate length of the second gate electrode layer, which is formed on the first gate electrode layer, is smaller than the dimension in the direction of gate length of the first gate electrode layer.
Claims19
A nonvolatile semiconductor storage device including a number of memory cells, each of the memory cells comprising:
- a semiconductor substrate;
- a tunnel insulating film formed on the semiconductor substrate;
- a charge storage layer formed on the tunnel insulating film;
- a block insulating film formed on the charge storage layer;
- and
- a gate electrode formed on the block insulating film, the gate electrode being structured such that at least first and second gate electrode layers are stacked, the first gate electrode layer is in contact with the block insulating film, the second gate electrode layer is formed on the first gate electrode layer and consists of a material different from that of the first gate electrode layer, and the second gate electrode layer has a smaller dimension in a direction of gate length than the first gate electrode layer.
A nonvolatile semiconductor storage device including a number of memory cells, each of the memory cells comprising:
- a semiconductor substrate;
- a tunnel insulating film formed on the semiconductor substrate;
- a charge storage layer formed on the tunnel insulating film;
- a block insulating film formed on the charge storage layer;
- and
- a gate electrode formed on the block insulating film, the gate electrode being structured such that first, second, and third gate electrode layers are stacked, the first gate electrode layer consists of a metal material and is in contact with the block insulating film, the second gate electrode layer is made from a polysilicon and is formed on the first gate electrode layer so that its edges opposed to each other in a direction of gate length back to the corresponding edges of the first gate electrode layer, and the third gate electrode layer is made from a metal silicide and formed on the second gate electrode layer.
Dependencies are inferred from the claim text.