Method for fabricating nonvolatile semiconductor memory device
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorToshinari Nitta
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Abstract
Ions of arsenic are selectively implanted at a high concentration into a substrate through a first passivation film of silicon dioxide to obtain a shallow junction, thereby forming a source region with a low resistivity and a first drain region. Then, after the first passivation film is removed, a second passivation film of silicon dioxide is deposited over the substrate as well as over a stacked cell electrode by a CVD process performed at a relatively low temperature. Thereafter, the substrate is annealed in a nitrogen ambient at such a temperature as activating the dopant introduced. In this manner, the dopant in source region and first drain region is activated.
Claims8
A method for fabricating a nonvolatile semiconductor memory device, the method comprising the steps of:
- a) forming a tunnel insulating film on a substrate and then selectively forming a floating gate electrode on the tunnel insulating film;
- b) forming a first passivation film on first and second regions of the substrate, the first and second regions being located below the floating gate electrode to horizontally sandwich the floating gate electrode therebetween;
- c) implanting ions of a first dopant into the substrate through the first passivation film with second region masked, thereby defining a doped region in the first region so that the doped region reaches a third region of the substrate, the third region being located around an end of the first region;
- d) removing the first passivation film and then forming a second passivation film on the first and second regions, said first dopant in the doped region not being actuated during formation of said second passivation film;
- and
- e) annealing the substrate, on which the second passivation film has been formed, in an inert gas ambient, thereby activating the first dopant in the doped region.
A method for fabricating a nonvolatile semiconductor memory device, the method comprising the steps of:
- a) forming a tunnel insulating film on a substrate and then selectively forming a floating gate electrode on the tunnel insulating film;
- b) forming a first passivation film on the substrate, at least covering a side of an edge portion of the tunnel insulating film under the floating gate electrode;
- c) implanting ions of a first dopant into the substrate through the first passivation film, thereby defining a first doped region in the substrate so that an edge portion of the first doped region reaches a region under the edge portion of the tunnel insulating film;
- d) removing the first passivation film and then forming a second passivation film on the substrate, at least covering a tunnel insulating film edge under the floating gate electrode, said first dopant not being actuated during formation of said second passivation film;
- e) annealing the substrate, on which the second passivation film has been formed, thereby activating the first dopant in the first doped region.
Dependencies are inferred from the claim text.