Methods of forming NAND cell units and NAND cell units
View Patent ↗Some embodiments include methods of forming charge storage transistor gates and standard FET gates in which common processing is utilized for fabrication of at least some portions of the different types of gates. FET and charge storage transistor gate stacks may be formed. The gate stacks may each include a gate material, an insulative material, and a sacrificial material. The sacrificial material is removed from the FET and charge storage transistor gate stacks. The insulative material of the FET gate stacks is etched through. A conductive material is formed over the FET gate stacks and over the charge storage transistor gate stacks. The conductive material physically contacts the gate material of the FET gate stacks, and is separated from the gate material of the charge storage transistor gate stacks by the insulative material remaining in the charge storage transistor gate stacks. Some embodiments include gate structures.
1. A NAND cell unit comprising:
a select gate comprising:
gate material;
electrically insulative material only partially covering the gate material leaving an opening;
a first conductive material in the opening; and
a second conductive material in the opening; and
a string gate spaced from the select gate.
2. The NAND cell unit of claim 1 wherein the first conductive material contacts the gate material.
3. The NAND cell unit of claim 1 wherein the first and second conductive material fill the opening in the electrically insulative material.
4. The NAND cell unit of claim 1 wherein the string gate further comprises the electrically insulative material.
5. The NAND cell unit of claim 4 wherein the electrically insulative material of the string gate has no opening.
6. The NAND cell unit of claim 4 wherein the electrically insulative material comprises a plurality of discrete layers.
7. The NAND cell unit of claim 1 wherein the electrically insulative material comprises a plurality of discrete layers.
8. The NAND cell unit of claim 1 wherein the string gate comprises gate material different from the gate material of the select gate.
9. The NAND cell unit of claim 8 wherein the gate material for the string gate comprises one or more charge-trapping compositions.
10. The NAND cell unit of claim 1 wherein the gate material comprises conductively-doped silicon.
11. The NAND cell unit of claim 1 wherein the gate material comprises conductively-doped silicon, and wherein the first conductive material comprises at least one metal.