Non-volatile memory and logic circuit process integration
View Patent ↗An integrated circuit is disclosed that includes a split gate memory device comprising a select gate is located over a substrate. A charge storage layer includes a layer of discrete storage elements and a layer of high-k dielectric material covering at least one side of the layer of discrete storage elements. At least a portion of a control gate is located over the charge storage layer. The control gate includes a layer of barrier work function material and a layer of gate material located over the layer of barrier work function material.
1. An integrated circuit comprising:
a split gate memory device comprising:
a select gate located over a substrate;
a charge storage layer including a layer of discrete storage elements and a layer of high-k dielectric material covering at least one side of the layer of discrete storage elements;
a control gate including at least a portion located over the charge storage layer, wherein the control gate includes a layer of barrier work function material and a first layer of gate material located over the layer of barrier work function material;
a transistor located in a different region of the substrate from the memory device, wherein the transistor includes a third gate structure, the third gate structure including a second layer of barrier work function material and a second layer of gate material located over the second layer of barrier work function material, wherein the first layer of gate material and the second layer of gate material are the same material deposited during a same process step and have a same thickness.
2. The integrated circuit of claim 1 wherein the charge storage layer includes a portion located laterally between the select gate and the control gate.
3. The integrated circuit of claim 1 wherein the discrete storage elements of the charge storage layer are characterized as nanocrystals formed from silicon.
4. The integrated circuit of claim 1 wherein a portion of the control gate is located over a top portion of the select gate.
5. The integrated circuit of claim 4 wherein a portion of the charge storage layer is located over the top portion of the select gate and below the portion of the control gate located over the top portion of the select gate.
6. The integrated circuit of claim 1 wherein the high-k dielectric material includes at least one of the group consisting of an oxide containing hafnium and an oxide containing aluminum.
7. The integrated circuit of claim 1 wherein the first and second layers of gate material include polysilicon.
8. The integrated circuit of claim 1 wherein the layer of barrier work function material includes at least one of the group consisting of tantalum nitride, titanium nitride, and tungsten nitride.
9. The integrated circuit of claim 1 wherein the layer of barrier work function material has a resistivity that is higher than a resistivity of the layer of gate material.
10. The integrated circuit of claim 1 wherein the second layer of barrier work function material is of a different material than the first layer of barrier work function material.
11. The integrated circuit of claim 1 wherein the charge storage layer further comprises:
a thermal oxide dielectric layer below at least some of the charge storage elements.
12. The integrated circuit of claim 1 wherein the first layer of gate material includes at least one of the group consisting of aluminum and tungsten.
13. An integrated circuit comprising:
a split gate memory device located at a first region of a substrate, the memory device comprising:
a charge storage layer including a layer of discrete storage elements and a layer of high-k dielectric material covering at least one side of the layer of discrete storage elements;
a select gate located under the charge storage layer;
a first gate located over the charge storage layer, the first gate including a first layer of barrier work function material and a first layer of gate material located having a first portion of a first thickness over the first layer of barrier work function material;
a transistor located at a second region of the substrate, the transistor comprising:
a second gate, the second gate including a second layer of barrier work function material and a second portion of the first layer of gate material of the first thickness located over the second layer of barrier work function material.
14. The integrated circuit of claim 13 wherein the second layer of barrier work function material is of a different material than the first layer of barrier work function material.
15. The integrated circuit of claim 13 wherein the second layer of barrier work function material is of a same material as the first layer of barrier work function material.
16. The integrated circuit of claim 13 wherein the second layer of gate material is of a same material as the first layer of gate material.
17. The integrated circuit of claim 13 wherein the transistor includes a high-k gate dielectric located below the second gate.
18. The integrated circuit of claim 13 wherein the discrete storage elements of the charge storage layer are characterized as silicon nanocrystals.