Method of ONO integration into logic CMOS flow
An embodiment of a method of integration of a non-volatile memory device into a logic MOS flow is described. Generally, the method includes: forming a pad dielectric layer of a MOS device above a first region of a substrate; forming a channel of the memory device from a thin film of semiconducting material overlying a surface above a second region of the substrate, the channel connecting a source and drain of the memory device; forming a patterned dielectric stack overlying the channel above the second region, the patterned dielectric stack comprising a tunnel layer, a charge-trapping layer, and a sacrificial top layer; simultaneously removing the sacrificial top layer from the second region of the substrate, and the pad dielectric layer from the first region of the substrate; and simultaneously forming a gate dielectric layer above the first region of the substrate and a blocking dielectric layer above the charge-trapping layer.
1. A method comprising:
forming above a surface on a substrate a stack of gate layers including at least two dielectric layers separated by at least one gate layer;
forming a non-volatile memory device in a first region of the stack of gate layers comprising:
forming a first opening extending from a top surface of the stack of gate layers to a lower surface of the stack of gate layers;
sequentially forming on sidewalls of the first opening a blocking dielectric, multiple charge-trapping layers and a tunnel oxide; and
forming on the tunnel oxide a thin layer of semiconducting material; and
forming a MOS device in a second region of the stack of gate layers,
wherein forming the multiple charge-trapping layers comprises forming a first charge-trapping layer comprising nitride over the blocking dielectric, forming an oxide anti-tunneling layer over the first charge-trapping layer by radical oxidation of a portion of the first charge-trapping layer, and forming a second charge-trapping layer over the oxide anti-tunneling layer.
2. The method of claim 1 , further comprising annealing junctions of the multiple charge-trapping layers.
3. The method of claim 1 , wherein the blocking dielectric comprises a high K dielectric.
4. The method of claim 3 , wherein the gate layer comprises metal.
5. The method of claim 1 , wherein the multiple charge-trapping layers comprise silicon oxynitride.
6. The method of claim 1 , wherein the first charge-trapping layer is oxygen-lean relative to the second charge-trapping layer and comprises a majority of charge traps distributed in the multiple charge-trapping layers.
7. A method comprising:
forming above a surface of a substrate a stack of layers including a dielectric layer separated from the substrate by at least one sacrificial layer;
forming in the stack of layers a first opening extending from a top surface to a lower surface of the stack of layers;
forming on sidewalls of the first opening a layer of semiconducting material;
forming in the stack of dielectric layers adjacent to the first opening a second opening extending from the top surface to the lower surface of the stack of layers, wherein the forming the second opening removes a portion of the sacrificial layer exposing a portion of the layer of semiconducting material;
forming on sidewalls of the second opening a number of dielectric layers including a tunnel oxide formed on sidewalls of the second opening, a first charge-trapping layer formed on the tunnel oxide, an anti-tunneling layer comprising oxide formed on the first charge-trapping layer, a second charge-trapping layer overlying the anti-tunneling layer, and a blocking dielectric formed on the second charge-trapping layer; and
depositing in the second opening over the number of dielectric layers a conducting material,
wherein the anti-tunneling layer is formed by radical oxidation of a portion of the first charge-trapping layer.
8. The method of claim 7 , wherein the second charge-trapping layer is oxygen-lean relative to the first charge-trapping layer and comprises a majority of charge traps distributed in the first and second charge-trapping layers.
9. The method of claim 7 , wherein the number of dielectric layers comprise a gate oxide, and wherein the layer of semiconducting material and the conducting material form a vertical channel and gate of a MOS device.
10. The method of claim 7 , further comprising annealing junctions of the first and second charge-trapping layers.
11. The method of claim 7 , wherein the blocking dielectric comprises a high K dielectric.
12. The method of claim 7 , wherein the conducting material comprises metal.
13. The method of claim 7 , wherein the first and second charge-trapping layers comprise silicon oxynitride.