Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
205 words
A method of making a three-dimensionally arranged ROM device, comprising: forming a plurality of parallel trenches in an upper surface of a silicon substrate, each trench having a bottom and a pair of sidewalls, and being separated from an adjacent trench by a respective one of a plurality of raised mesa regions; depositing a silicon nitride layer over the silicon substrate; patterning the silicon nitride layer to expose a portion of the trench bottoms, and a portion of the raised mesa regions, and thereby forming a plurality of silicon nitride layers; using the patterned silicon nitride layers as a mask, and implanting ions in the exposed portions to form a plurality of source/drain regions with the unexposed portions of the trench bottoms and the raised mesa regions forming channel regions; forming a plurality of sidewall oxide layers on the respective trench sidewalls; removing selected sidewall oxide layers for program coding of the ROM device; removing selected silicon nitride layers for program coding of the ROM device; forming a gate oxide layer over the upper surface of the silicon substrate; depositing a polysilicon layer over the silicon nitride layers and gate oxide layer; and patterning the polysilicon layer to form a plurality of polysilicon word lines.
Claim 2
Independent Claim
205 words
A method of making a three-dimensionally arranged ROM device, comprising: forming a plurality of parallel trenches in an upper surface of a silicon substrate, each trench having a bottom and a pair of sidewalls, and being separated from an adjacent trench by a respective one of a plurality of raised mesa regions; depositing a silicon nitride layer over the silicon substrate; patterning the silicon nitride layer to expose a portion of the trench bottoms, and a portion of the raised mesa regions, and thereby forming a plurality of silicon nitride layers; using the patterned silicon nitride layers as a mask, and implanting ions in the exposed portions to form a plurality of source/drain regions with the unexposed portions of the trench bottoms and the raised mesa regions forming channel regions; forming a plurality of sidewall oxide layers on the respective trench sidewalls; removing selected sidewall oxide layers for program coding of the ROM device; removing selected silicon nitride layers for program coding of the ROM device; forming a gate oxide layer over the upper surface of the silicon substrate; depositing a polysilicon layer over the silicon nitride layers and gate oxide layer; and patterning the polysilicon layer to form a plurality of polysilicon word lines.
Claim 3
Dependent Claim
35 words
The method defined in claim 1, wherein said forming a plurality of parallel trenches includes forming the trenches to a depth roughly equal to a width of two source/drain regions and a channel region combined.
Claim 4
Dependent Claim
30 words
The method defined in claim 1, wherein said depositing a silicon nitride layer includes depositing the silicon nitride layer to a thickness between about 1500 Å and about 3000 Å.
Claim 5
Dependent Claim
41 words
The method defined in claim 1, wherein said implanting ions includes implanting arsenic ions having an energy between about 50 KeV and about 100 KeV, and a dosage between about 1×10 14 atoms/cm 2 and about 1×10 16 atoms/cm 2 .
Claim 6
Dependent Claim
41 words
The method defined in claim 1, wherein said implanting ions includes implanting phosphorus ions having an energy between about 20 KeV and about 60 KeV and a dosage between about 1×10 14 atoms/cm 2 and about 1×10 16 atoms/cm 2 .
Claim 7
Dependent Claim
30 words
The method defined in claim 1, wherein said forming a gate oxide layer includes forming the gate oxide layer to a thickness between about 50 Å and about 250 Å.