Semiconductor device having nitridated oxide layer and method therefor
View Patent ↗A semiconductor device includes a substrate ( 12 ), a first insulating layer ( 14 ) over a surface of the substrate ( 12 ), a layer of nanocrystals ( 13 ) over a surface of the first insulating layer ( 14 ), a second insulating layer ( 15 ) over the layer of nanocrystals ( 13 ). A nitriding ambient is applied to the second insulating layer ( 15 ) to form a barrier to further oxidation when a third insulating layer ( 22 ) is formed over the substrate ( 12 ). The nitridation of the second insulating layer ( 15 ) prevents oxidation or shrinkage of the nanocrystals and an increase in the thickness of the first insulating layer 14 without adding complexity to the process flow for manufacturing the semiconductor device ( 10 ).
1. A semiconductor device comprising:
a semiconductor substrate;
a first insulating layer formed over a surface of the semiconductor substrate;
a patterned layer of nanocrystals formed over a surface of the first insulating layer;
a second insulating layer formed over the layer of nanocrystals, the second insulating layer having a nitrogen content greater than or equal to two (2) atomic percent of the second insulating layer;
a third insulating layer formed on the surface of the semiconductor substrate and not over the first and second insulating layer; and
a patterned polysilicon layer formed over the second insulating layer and over the third insulating layer, wherein the patterned polysilicon layer over the second insulating layer forms gate electrodes for a plurality of non-volatile memory cells, and wherein the patterned polysilicon layer over the third insulating layer forms gate electrodes for a plurality of transistors.
2. The semiconductor device of claim 1 , wherein one of plasma nitridation, thermal nitridation, or ion nitridation is used to produce the nitrogen content of the second insulating layer.
3. The semiconductor device of claim 1 , wherein the second insulating layer comprises a laminate of insulating layers.
4. The semiconductor device of claim 1 , wherein the semiconductor device is annealed at between about 400 to 1000 degrees Celsius.
5. The semiconductor device of claim 1 , wherein the nitrogen content of the second insulating layer is provided using a nitriding ambient including one or more of ammonia, nitrous oxide, atomic nitrogen, or other nitrogen compound.
6. The semiconductor device of claim 1 , wherein the semiconductor device includes a plurality of non-volatile memory cells.
7. The semiconductor device of claim 1 , wherein the nitrogen content of the second insulating layer provides an oxidation barrier.
8. The semiconductor device of claim 1 , wherein the nanocrystals are formed from silicon.