Isolated-nitride-region non-volatile memory cell and fabrication method
View Patent ↗An isolated-nitride-region non-volatile memory cell is formed in a semiconductor substrate. Spaced-apart source and drain regions are disposed in the semiconductor substrate forming a channel therebetween. An insulating region is disposed over the semiconductor substrate. A gate is disposed over the insulating region and is horizontally aligned with the channel. A plurality of isolated nitride regions are disposed in the insulating region and are not in contact with either the channel or the gate.
1. A method for fabricating an isolated-nitride-region non-volatile memory cell comprising:
forming a tunnel dielectric on a semiconductor substrate;
forming a nitride layer over the tunnel dielectric to define a channel region;
forming silicon nano-crystals on the nitride layer;
selectively etching the nitride layer to form isolated nitride regions using the silicon nano-crystals as a mask;
forming a dielectric layer over the isolated nitride regions to encapsulate the isolated nitride regions;
forming a gate over the channel region; and
forming source and drain regions in the semiconductor substrate, the source and drain regions being horizontally aligned with the gate.
2. The method of claim 1 , wherein forming the nitride layer comprises forming a silicon nitride layer.
3. The method of claim 1 , wherein forming the nitride layer comprises forming a titanium nitride layer.
4. The method of claim 1 , further including forming a layer over the tunnel dielectric prior to forming the nitride layer.
5. The method of claim 4 wherein forming a layer over the tunnel dielectric prior to forming the nitride layer comprises forming a layer of one of tungsten, titanium, silicon and germanium.