摘要:
A polysilicon-based floating gate is formed so as to be resistant to oxidation that occurs during multiple thermo-cycles in fabrication. Accordingly, edge erase times in NOR-type memory devices may be minimized. Additionally, manufacture of oxidation resistant floating gates reduces variations in edge erase times among multiple NOR-type memory devices. A layer of amorphous silicon is deposited over a silicon substrate by directing a mixture of silane and a phosphene-helium gas mixture at the surface of the silicon substrate. Later, N+ ions are implanted into the amorphous silicon. The amorphous silicon layer is then etched so as to overlap slightly with regions that will later correspond to the source and drain regions. Next, a lower oxide layer of an ONO dielectric is deposited and the device is heated. A thermo-cycle is eliminated by heating the amorphous silicon during formation of the oxide layer rather than immediately following its deposition. Later, the nitride and oxide layers of the ONO dielectric, a second polysilicon layer, a tungsten silicide layer, and SiON layers are successively formed.
摘要:
In one embodiment, the present invention relates to a method of forming a flash memory cell, involving the steps of forming a tunnel oxide on a substrate; forming a first polysilicon layer over the tunnel oxide; forming an insulating layer over the first polysilicon layer; forming a second polysilicon layer over the insulating layer by depositing an second polysilicon layer having a first thickness, and then using chemical mechanical polishing to form a second polysilicon layer having a second thickness, wherein the second thickness is at least about 25% less than the first thickness; forming a tungsten silicide layer over the second polysilicon layer by chemical vapor deposition using WF6 and SiH4; etching at least the first polysilicon layer, the second polysilicon layer, the insulating layer, and the tungsten silicide layer thereby defining at least one stacked gate structure; and forming a source region and a drain region in the substrate, thereby forming at least one memory cell.
摘要:
In one embodiment, the present invention relates to a method of forming a flash memory cell involving the steps of: forming a tunnel oxide on a substrate; forming an in situ phosphorus doped polysilicon layer over the tunnel oxide by low pressure chemical vapor deposition at a temperature between about 610.degree. C. and about 630.degree. C., wherein the in situ phosphorus doped polysilicon layer comprises from about 1.times.10.sup.19 atoms/cm.sup.3 to about 5.times.10.sup.19 atoms/cm.sup.3 of phosphorus; forming an insulating layer over the in situ phosphorus doped polysilicon layer; forming a conductive layer over the insulating layer; etching the in situ phosphorus doped polysilicon layer, the conductive layer and the insulating layer, thereby defining one or more stacked gate structures; and forming a source region and a drain region in the substrate, wherein the source region and the drain region are self-aligned by the stacked gate structures, thereby forming one or more memory cells.
摘要:
In one embodiment, the present invention relates to a method of forming a flash memory cell, involving the steps of forming a tunnel oxide on a substrate; forming a first polysilicon layer over the tunnel oxide; forming an insulating layer over the first polysilicon layer, the insulating layer comprising an oxide layer made by low pressure chemical vapor deposition at a temperature from about 600.degree. C. to about 850.degree. C. using SiH.sub.4 and N.sub.2 O, annealing in an NH.sub.3 atmosphere at a temperature from about 800.degree. C. to about 900.degree. C., and wet oxidizing using O.sub.2 and H.sub.2 at a temperature from about 820.degree. C. to about 880.degree. C.; forming a second polysilicon layer over the insulating layer; etching at least the first polysilicon layer, the second polysilicon layer and the insulating layer, thereby defining at least one stacked gate structure; and forming a source region and a drain region in the substrate, thereby forming at least one memory cell.
摘要:
Polystringers that cause NAND-type memory core cells to malfunction are removed. A SiON layer, tungsten silicide layer, second polysilicon layer, ONO dielectric, and first polysilicon layer are successively removed from between NAND-type flash memory core cells leaving ONO fence that shields some first polysilicon layer material from removal. Next, the device is exposed to oxygen gas in a high temperature environment to oxidize the surface of the device, and in particular to remove the polystringers.
摘要:
In one embodiment, the present invention relates to a method of forming a flash memory cell, involving the steps of forming a tunnel oxide on a substrate; forming a first polysilicon layer over the tunnel oxide; forming an insulating layer over the first polysilicon layer, the insulating layer comprising a first oxide layer over the first polysilicon layer, a nitride layer over the first oxide layer, and a second oxide layer over the nitride layer, wherein the second oxide layer is made by forming the second oxide layer by low pressure chemical vapor deposition at a temperature from about 600.degree. C. to about 850.degree. C. using SiH.sub.4 and N.sub.2 O and annealing in an N.sub.2 O atmosphere at a temperature from about 700.degree. C. to about 950.degree. C.; forming a second polysilicon layer over the insulating layer; etching at least the first polysilicon layer, the second polysilicon layer and the insulating layer, thereby defining at least one stacked gate structure; and forming a source region and a drain region in the substrate, thereby forming at least one memory cell.
摘要:
In one embodiment, the present invention relates to a method of forming a flash memory cell, involving the steps of forming a tunnel oxide on a substrate; forming a first polysilicon layer over the tunnel oxide; forming an insulating layer over the first polysilicon layer, the insulating layer comprising an oxide layer over the first polysilicon layer, and a tantalum pentoxide layer over the oxide layer, wherein the tantalum pentoxide layer is made by chemical vapor deposition at a temperature from about 200° C. to about 650° C. using an organic tantalum compound and an oxygen compound, and heating in an N2O atmosphere at a temperature from about 700° C. to about 875° C.; forming a second polysilicon layer over the insulating layer; etching at least the first polysilicon layer, the second polysilicon layer and the insulating layer, thereby defining at least one stacked gate structure; and forming a source region and a drain region in the substrate, thereby forming at least one memory cell.
摘要:
In one embodiment, the present invention relates to a method of cleaning a low pressure chemical vapor deposition apparatus having TEOS material build-up therein involving contacting the low pressure chemical vapor deposition apparatus with a composition containing at least one lower alcohol. In another embodiment, the present invention relates to a system for cleaning a low pressure chemical vapor deposition apparatus having TEOS material build-up therein, containing a supply of a composition comprising at least one lower alcohol; an injection port for introducing the composition comprising at least one lower alcohol into the low pressure chemical vapor deposition apparatus; and a pump/vacuum system for removing crystallized TEOS material build-up from the low pressure chemical vapor deposition apparatus.
摘要:
In one embodiment, the present invention relates to a method of forming a flash memory cell involving the steps of forming a tunnel oxide on a substrate; forming a first polysilicon layer over the tunnel oxide; forming an insulating layer over the first polysilicon layer, the insulating layer comprising a first oxide layer over the first polysilicon layer, a nitride layer over the first oxide layer, and a second oxide layer over the nitride layer, wherein the second oxide layer is made by forming the second oxide layer by rapid thermal chemical vapor deposition at a temperature from about 780.degree. C. to about 820.degree. C. using SiH.sub.4 and N.sub.2 O and annealing in an N.sub.2 O atmosphere a temperature from about 980.degree. C. to about 1020.degree. C.; forming a second polysilicon layer over the insulating layer; etching at least the first polysilicon layer, the second polysilicon layer and the insulating layer, thereby defining at least one stacked gate structure; and forming a source region and a drain region in the substrate, wherein the source region and the drain region are self-aligned by the stacked gate structure, thereby forming at least one memory cell.
摘要:
In one embodiment, the present invention relates to a method of cleaning a low pressure chemical vapor deposition apparatus having TEOS material build-up therein involving contacting the low pressure chemical vapor deposition apparatus with a composition containing at least one lower alcohol. In another embodiment, the present invention relates to a system for cleaning a low pressure chemical vapor deposition apparatus having TEOS material build-up therein, containing a supply of a composition comprising at least one lower alcohol; an injection port for introducing the composition including at least one lower alcohol into the low pressure chemical vapor deposition apparatus; and a pump/vacuum system for removing crystallized TEOS material build-up from the low pressure chemical vapor deposition apparatus.