Gettering agents in memory charge storage structures
Methods of forming memory cells including a charge storage structure having a gettering agent therein can be useful for non-volatile memory devices. Providing for gettering of oxygen from a charge-storage material of the charge storage structure can facilitate a mitigation of detrimental oxidation of the charge-storage material.
1. A method of forming a memory cell, comprising:
forming a first dielectric over a semiconductor;
forming a charge storage structure over the first dielectric;
forming a second dielectric over the charge storage structure;
forming a control gate over the second dielectric; and
forming source/drain regions in the semiconductor generally adjacent the first dielectric;
wherein forming the charge storage structure comprises:
forming a charge-storage material; and
incorporating a gettering agent into the charge storage structure at more than a stoichiometric amount.
2. The method of claim 1 , wherein incorporating a gettering agent into the charge storage structure comprises incorporating the gettering agents using a process selected from the group consisting of ionic implantation, sputtering, plasma, and chemical vapor deposition.
3. The method of claim 1 , wherein the gettering agent comprises an oxygen gettering agent.
4. The method of claim 1 , wherein forming a charge storage structure comprises forming a charge storage structure that has a conductivity selected from the group consisting of semiconductive and conductive.
5. A method of forming a memory cell, comprising:
forming a first dielectric over a semiconductor;
forming a charge storage structure over the first dielectric;
forming a second dielectric over the charge storage structure;
forming a control gate over the second dielectric; and
forming source/drain regions in the semiconductor generally adjacent the first dielectric;
wherein forming the charge storage structure comprises:
forming a charge-storage material; and
incorporating a gettering agent into the charge-storage material comprising implanting the gettering agent into the charge-storage material.
6. The method of claim 5 , wherein incorporating the gettering agent into the charge-storage material comprises incorporating the gettering agent into only a portion of the charge-storage material.
7. The method of claim 1 , wherein incorporating a gettering agent into the charge storage structure comprises forming the gettering agent on top of the charge-storage material.
8. The method of claim 1 , wherein incorporating a gettering agent into the charge storage structure comprises incorporating the gettering agent to have a concentration of the gettering agent near an interface of the charge storage structure and the second dielectric that is higher than a concentration of the gettering agent near an interface of the charge storage structure and the first dielectric.
9. A method of forming a memory cell, comprising:
forming a first dielectric over a semiconductor;
forming a silicon-containing material over the first dielectric;
incorporating a metal into the silicon-containing material;
annealing to react at least a portion of the metal with the silicon-containing material, thereby defining a charge storage structure;
forming a second dielectric over the charge storage structure;
forming a control gate over the second dielectric; and
forming source/drain regions in the semiconductor generally adjacent the first dielectric.
10. The method of claim 9 , wherein incorporating a metal into the silicon-containing material comprises incorporating a sufficient amount of the metal such that unreacted metal remains in the charge storage structure after annealing to react the at least a portion of the metal with the silicon-containing material.
11. The method of claim 9 , wherein annealing to react at least a portion of the metal with the silicon-containing material comprises forming at least one compound selected from the group consisting of a metal silicon oxide, a metal silicide and a metal oxide.
12. The method of claim 9 , wherein the silicon-containing material contains a silicon oxide and further comprising reacting the at least a portion of the metal with the silicon-containing material to convert at least a portion of the silicon oxide to a metal silicon oxide, or silicon and a metal oxide.
13. The method of claim 9 , wherein the silicon-containing material contains a silicon oxide and further comprising reacting the at least a portion of the metal with the silicon-containing material to convert at least a portion of the silicon oxide to a compound that is either conductive or has a dielectric constant greater than a dielectric constant of silicon dioxide.
14. The method of claim 9 , further comprising:
preferentially reacting oxygen with at least a further portion of the metal over the silicon-containing material.
15. The method of claim 9 , wherein reaction products from annealing to react at least a portion of the metal with the silicon-containing material separate remaining portions of the silicon-containing material from the second dielectric.
16. A method of forming a memory cell, comprising:
forming a first dielectric over a semiconductor;
forming an instance of charge-storage material over the first dielectric;
forming an instance of metal, wherein the instance of metal is formed over the instance of charge-storage material;
reacting the instance of charge-storage material with only a portion of the instance of metal, thereby defining a charge storage structure containing an unreacted portion of the instance of metal;
forming a second dielectric over the charge storage structure;
forming a control gate over the second dielectric; and
forming source/drain regions in the semiconductor generally adjacent the first dielectric.
17. The method of claim 16 , wherein reacting the instance of charge-storage material with the at least a portion of the instance of metal occurs during or after forming the second dielectric.
18. A method of forming a memory cell, comprising:
forming a first dielectric over a semiconductor;
forming two or more instances of charge-storage material over the first dielectric;
forming two or more instances of metal, wherein each instance of metal is formed over a corresponding instance of charge-storage material;
reacting each instance of charge-storage material with at least a portion of its corresponding instance of metal, thereby defining a charge storage structure;
forming a second dielectric over the charge storage structure;
forming a control gate over the second dielectric; and
forming source/drain regions in the semiconductor generally adjacent the first dielectric.
19. The method of claim 18 , wherein each successive instance of charge-storage material is thinner than a prior instance of charge-storage material, while each successive instance of metal is thicker than a prior instance of metal.
20. The method of claim 18 , wherein each successive instance of charge-storage material is thinner than a prior instance of charge-storage material, while each instance of metal has a uniform thickness.
21. The method of claim 18 , wherein each successive instance of metal is thicker than a prior instance of metal, while each instance of charge-storage material has a uniform thickness.
22. The method of claim 5 , wherein implanting the gettering agent into the charge-storage material comprises implanting the gettering agent using a process selected from a group consisting of ionic implantation and plasma deposition.