Sonos device and method for fabricating the same
View Patent ↗A silicon-oxide-nitride-oxide-silicon (SONOS) device is disclosed. The SONOS device includes a substrate; a first oxide layer on the substrate; a silicon-rich trapping layer on the first oxide layer; a nitrogen-containing layer on the silicon-rich trapping layer; a silicon-rich oxide layer on the nitrogen-containing layer; and a polysilicon layer on the silicon-rich oxide layer.
1. A method for fabricating silicon-oxide-nitride-oxide-silicon (SONOS) device, comprising:
providing a substrate;
forming a first oxide layer on the substrate;
forming a silicon nitride (SiN) layer on the first oxide layer;
performing a first silane soak process;
injecting ammonia and silane for forming a silicon-rich SiN layer on the silicon nitride layer;
forming a nitrogen-containing layer on the silicon-rich SiN layer;
forming a silicon-rich oxide layer on the nitrogen-containing layer; and
forming a polysilicon layer on the silicon-rich oxide layer.
2. The method for fabricating SONOS device of claim 1 , further comprising:
performing an ammonia soak on the first oxide layer; and
injecting ammonia and silane for forming the silicon nitride layer.
3. The method for fabricating SONOS device of claim 1 , further comprising performing a microwave plasma-enhanced chemical vapor deposition (PECVD) process for forming the silicon nitride layer.
4. The method for fabricating SONOS device of claim 1 , further comprising:
performing the first silane soak process under plasma off on the silicon nitride layer; and
injecting ammonia and silane with plasma on for forming the silicon-rich SiN layer.
5. The method for fabricating SONOS device of claim 1 , wherein the nitrogen-containing layer comprises a silicon nitride layer.
6. The method for fabricating SONOS device of claim 1 , wherein the nitrogen-containing layer comprises a silicon oxynitride layer.
7. The method for fabricating SONOS device of claim 6 , further comprising:
performing a second silane soak process under plasma off on the nitrogen-containing layer; and
injecting ammonia, oxygen, and silane with plasma on for forming the silicon-rich oxide layer.
8. The method for fabricating SONOS device of claim 1 , further comprising forming a second oxide layer on the silicon-rich oxide layer before forming the polysilicon layer.
9. The method for fabricating SONOS device of claim 1 , wherein the first silane soak process comprises conducting a helium (He) pre-clean process at a temperature greater than 300° C.
10. The method for fabricating SONOS device of claim 1 , wherein the first silane soak process is performed under atmospheric or sub-atmospheric environment in the same chamber.
11. A method for fabricating silicon-oxide-nitride-oxide-silicon (SONOS) device, comprising:
providing a substrate;
forming a first oxide layer on the substrate;
forming a silicon nitride (SiN) layer on the first oxide layer;
performing a first silane soak process;
injecting ammonia, oxygen, and silane for forming a silicon-rich SiON layer on the silicon nitride layer;
forming a nitrogen-containing layer on the silicon-rich SiON layer;
forming a silicon-rich oxide layer on the nitrogen-containing layer; and
forming a polysilicon layer on the silicon-rich oxide layer.