Self-aligned channel drift device and methods of making such a device
One illustrative device includes a source region and a drain region formed in a substrate, wherein the source/drain regions are doped with a first type of dopant material, a gate structure positioned above the substrate that is laterally positioned between the source region and the drain region and a drain-side well region positioned in the substrate under a portion, but not all, of the entire lateral width of the drain region, wherein the drain-side well region is also doped with the first type of dopant material. The device also includes a source-side well region positioned in the substrate under an entire width of the source region and under a portion, but not all, of the drain region and a part of the extension portion of the drain region is positioned under a portion of the gate structure.
1. A device, comprising:
an isolation region positioned in a semiconductor substrate, said isolation region laterally defining and electrically isolating a device region comprising said device;
a source region and a drain region formed in said substrate, said source and drain regions being doped with a first type of dopant material;
a gate structure positioned above said substrate, said gate structure being generally laterally positioned between said source region and said drain region;
a drain-side well region positioned in said substrate under a portion, but not all, of said drain region, said drain-side well region being doped with said first type of dopant material; and
a source-side well region positioned in said substrate under an entire width of said source region, under an entire width of said gate structure and under a portion, but not all, of said drain region, said source-side well region being doped with a second type of dopant material that is opposite to said first type of dopant material, wherein said source region doped with said first type of dopant material extends laterally across said source-side well region from at least a source-side edge of said gate structure to a source-side inner edge of said isolation region.
2. The device of claim 1 , wherein said drain region comprises an extension portion and wherein a part of said extension portion is positioned under a portion of said gate structure.
3. The device of claim 1 , wherein said drain region has a maximum lateral width that is wider than a maximum lateral width of said drain-side well region.
4. The device of claim 1 , wherein said source-side well region contacts said drain-side well region at a point that is laterally positioned between a drain-side edge of said gate structure and a drain-side inner edge of said isolation region.
5. The device of claim 1 , wherein said source-side well region has a lateral width that is wider than a combined lateral width of said source region and said gate structure.
6. The device of claim 1 , wherein said first type of dopant material is an N-type dopant and said second type of dopant material is a P-type dopant.
7. The device of claim 1 , wherein said first type of dopant material is a P-type dopant and said second type of dopant material is an N-type dopant.
8. The device of claim 1 , wherein said drain region doped with said first type of dopant material extends laterally across a portion of said source-side well region and across an entirety of said drain-side well region from said drain-side edge of said gate structure to a drain-side inner edge of said isolation region.
9. The device of claim 1 , wherein said gate structure is a first gate structure, said source region is a first source region, said drain region is a first drain region, and said source-side well region is a first source-side well region, the device further comprising:
a second source region formed in said substrate, wherein said second source region is doped with said first type of dopant material, said drain region is a single common drain region, and said drain-side well region is a single common drain-side well region;
a second gate structure positioned above said substrate, said second gate structure being generally laterally positioned between said second source region and said single common drain region;
a second source-side well region positioned in said substrate laterally adjacent to said drain-side well region and opposite of said first source-side well region, said second source-side well region extending under an entire width of said second source region, under an entire width of said second gate structure, and under a second portion, but not all, of said single common drain region, said second source-side well region being doped with said second type of dopant material, wherein said single common drain region doped with said first type of dopant material extends laterally across a portion of said first source-side well region, an entirety of said drain-side well region, and a portion of said second source-side well region from a drain-side edge of said first gate structure to a drain-side edge of said second gate structure.
10. A device, comprising:
an isolation region positioned in a semiconductor substrate, said isolation region laterally defining and electrically isolating a device region comprising said device;
a source region and a drain region formed in said substrate, said source and drain regions being doped with a first type of dopant material, said drain region comprising an extension region that defines a maximum lateral width of said drain region;
a gate structure positioned above said substrate, said gate structure being generally laterally positioned between said source region and said drain region;
a drain-side well region positioned in said substrate under a portion, but not all, of said drain region, said drain-side well region being doped with said first type of dopant material and having a lateral width that is less than said maximum lateral width of said drain region; and
a source-side well region positioned in said substrate under at least said source region, said source-side well region being doped with a second type of dopant material that is opposite to said first type of dopant material, wherein said source region doped with said first type of dopant material extends laterally across said source-side well region from a source-side edge of said gate structure to a source-side inner edge of said isolation region.
11. The device of claim 10 , wherein said drain region comprises an extension portion and wherein a part of said extension portion is positioned under a portion of said gate structure.
12. The device of claim 10 , wherein said source-side well region is further positioned under an entire width of said gate structure and under a portion, but not all, of said drain region.
13. The device of claim 10 , wherein said source-side well region contacts said drain-side well region at a point that is laterally positioned between a drain-side edge of said gate structure and a drain-side inner edge of said isolation region.
14. The device of claim 10 , wherein said source-said well region has a lateral width that is wider than a combined lateral width of said source region and said gate structure.
15. The device of claim 10 , wherein said drain region doped with said first type of dopant material extends laterally across a portion of said source-side well region and across an entirety of said drain-side well region from said drain-side edge of said gate structure to a drain-side inner edge of said isolation region.
16. A device, comprising:
an isolation region positioned in a semiconductor substrate so as to electrically isolate said device;
a source region and a drain region formed in said substrate, said source and drain regions being doped with a first type of dopant material, said drain region comprising an extension region that defines a maximum lateral width of said drain region;
a gate structure positioned above said substrate, said gate structure being generally laterally positioned between said source region and said drain region, wherein a part of said extension region of said drain region is positioned under a portion of said gate structure;
a drain-side well region positioned in said substrate under a portion, but not all, of said drain region, said drain-side well region being doped with said first type of dopant material, wherein a maximum lateral width of said drain-side well region is less than said maximum lateral width of said drain region; and
a source-side well region positioned in said substrate, said source-side well region being doped with a second type of dopant material that is opposite to said first type of dopant material, wherein said source region doped with said first type of dopant material extends laterally across said source-side well region from a source-side edge of said gate structure to a source-side inner edge of said isolation region, and wherein said source-side well region contacts said drain-side well region at a point that is laterally positioned between a drain-side edge of said gate structure and a drain-side inner edge of said isolation region.
17. The device of claim 16 , wherein said drain region has a maximum lateral width that is wider than a maximum lateral width of said drain-side well region.
18. The device of claim 16 , wherein said source-side well region is positioned under an entire width of said source region, under an entire width of said gate structure and under a portion, but not all, of said drain region.
19. The device of claim 16 , wherein said source-side well region has a lateral width that is wider than a combined lateral width of said source region and said gate structure.
20. The device of claim 16 , wherein said drain region doped with said first type of dopant material extends laterally across a portion of said source-side well region and across an entirety of said drain-side well region from said drain-side edge of said gate structure to said drain-side inner edge of said isolation region.