Flash memory device and method for fabricating the same
View Patent ↗A flash memory device and a method for fabricating the same is disclosed that reduces or prevents mis-operation and improves integration, which includes a semiconductor substrate having a field region and an active region; a device isolation layer on the field region including a conductive (e.g., polysilicon) layer and an insulating layer thereon; a sidewall spacer at sides of the device isolation layer; an ONO layer on the active region; a gate electrode on the ONO layer; source and drain regions at sides of the gate electrode in the active region; a passivation layer on the semiconductor substrate, having a contact hole in the drain region; and a drain electrode in the contact hole, connected with the drain region.
1. A method for fabricating a flash memory device comprising:
forming a device isolating layer having a stack structure comprising a first insulating layer, a conductive layer and a second insulating layer on a field region of a semiconductor substrate;
forming an insulating sidewall spacer at a side of the device isolation layer;
forming an ONO layer on an active region of the semiconductor substrate, and forming a gate electrode on the ONO layer;
forming source and drain regions by implanting impurity ions into the active region of the semiconductor substrate using the gate electrode as a mask; and
forming a passivation layer on an entire surface of the semiconductor substrate, and forming a contact hole in the passivation layer over the drain region.
2. The method of claim 1 , wherein the contact hole exposes the drain region of the semiconductor substrate and part of the insulating sidewall spacer.
3. The method of claim 1 , wherein the conductive layer comprises polysilicon.
4. The method of claim 3 , further comprising oxidizing a side of the polysilicon layer of the device isolation layer before forming the insulating sidewall spacer.
5. The method of claim 1 , further comprising oxidizing an exposed surface of the gate electrode before forming the source and drain regions.
6. The method of claim 1 , wherein the first insulating layer comprises a first oxide layer and the second insulating layer comprises a second oxide layer and a nitride layer on the second oxide layer.
7. The method of claim 1 , wherein the contact hole is self aligned to the insulating sidewall spacer.
8. The method of claim 1 , further comprising forming a drain electrode in the contact hole, connected to the drain region.
9. The method of claim 1 , further comprising grounding the conductive layer of the device isolation layer.