Method for forming a semiconductor-on-insulator (SOI) body-contacted device with a portion of drain region removed
View Patent ↗A method for making a semiconductor device includes patterning a semiconductor layer, overlying an insulator layer, to create a first active region and a second active region, wherein the first active region is of a different height from the second active region, and wherein at least a portion of the first active region has a first conductivity type and at least a portion of the second active region has a second conductivity type different from the first conductivity type in at least a channel region of the semiconductor device. The method further includes forming a gate structure over at least a portion of the first active region and the second active region. The method further includes removing a portion of the second active region on one side of the semiconductor device.
1. A method of making a semiconductor device, comprising:
forming a semiconductor layer, overlying an insulator layer, to create a first active region and a second active region, wherein the first active region is of a different height from the second active region, and wherein at least a portion of the first active region is lightly doped and at least a portion of the second active region is heavily doped;
forming a gate structure over a top portion and sidewall portions of the first active region and over at least a portion of the second active region, wherein a drain region is located on a first side of the gate structure and a source region is located on a second side, opposite the first side, of the gate structure, and wherein a channel region is located between the drain region and the source region and along the top portion and sidewall portions of the first active region, adjacent the gate structure; and
after forming the gate structure, removing a portion of the second active region from only the drain region to expose the insulator layer.
2. The method of claim 1 , wherein the at least a portion of the first active region is P− and the at least a portion of the second active region is P+.
3. The method of claim 1 further comprising masking the first active region and performing an implant into the second active region.
4. The method of claim 3 , wherein the forming the gate structure further comprises forming a gate dielectric over the first active region and the second active region.
5. The method of claim 4 , wherein the forming the gate structure further comprises forming a gate electrode layer over the gate dielectric.
6. The method of claim 5 , wherein the removing the portion of the second active region from only the drain region further comprises masking the source region of the semiconductor device.
7. The method of claim 6 further comprising implanting dopants of a conductivity type opposite to a conductivity type of a semiconductor region under the gate structure.
8. The method of claim 7 further comprising siliciding the first active region and the second active region to form a silicide region connecting the first active region and the second active region.
9. The method of claim 8 further comprising forming at least one contact over the silicide region, wherein the at least one contact overlaps at least a part of the first active region and at least a part of the second active region.
10. The method of claim 1 , further comprising:
forming a silicide region in the source region that connects a portion of the first active region in the source region to a portion of the second active region in the source region, wherein the first active region includes a body region between the sidewalls of the first active region, outside the channel region and under the gate structure, and wherein the silicide region provides a connection between the body region and the portion of the first active region in the source region, and wherein the silicide region in the source region extends through the portion of the second active region in the source region to the insulator layer.
11. The method of claim 1 , wherein patterning the semiconductor layer further comprises creating a third active region adjacent the second active region, and a fourth active region adjacent the third active region, the second active region between the first and third active regions, and the third active region between the second and fourth active regions, and wherein the forming the gate structure comprises forming the gate structure over at least a portion of the third and fourth active regions, wherein portions of the first and third active regions underlying the gate structure have a same height and same conductivity type, and portions of the second and fourth active regions underlying the gate structure have a same height and same conductivity type.
12. The method of claim 11 , wherein the channel region is also located along a top portion and sidewall portions of the third active region adjacent the gate structure.
13. The method of claim 11 , wherein the removing the portion of the second active region from only the drain region to expose the insulator layer comprises removing portions of the second and fourth active regions from only the drain region to expose the underlying insulator layer.
14. A method of making a semiconductor device, comprising:
forming a semiconductor layer, overlying an insulator layer, wherein the semiconductor layer includes a first active region and a second active region, wherein the first active region is of a different height from the second active region;
forming a gate structure over a top portion and sidewall portions of the first active region and over at least a portion of the second active region, wherein a channel region is located along the top portion and the sidewall portions of the first active region, adjacent the gate structure, and wherein the channel region is lightly doped with a first conductivity type and the at least a portion of the second active region under the gate structure is heavily doped with the first conductivity type, and
after forming the gate structure, removing a portion of the second active region from only a drain region of the semiconductor device to expose the insulator layer.
15. The method of claim 14 , further comprising performing a source/drain implant wherein, after the source/drain implant, a portion of the first active region extending out from under the gate structure has an opposite conductivity type from the first conductivity type.
16. The method of claim 14 , further comprising forming a silicide region in a source region of the semiconductor device, that connects a portion of the first active region in the source region to a portion of the second active region in the source region, the silicide region extending through the portion of the second active region in the source region to the insulator layer.
17. The method of claim 14 , wherein the semiconductor layer further comprises a third active region adjacent the second active region, and a fourth active region adjacent the third active region, the second active region between the first and third active regions, and the third active region between the second and fourth active regions, and wherein the forming the gate structure further comprises forming the gate structure over at least a portion of the third and fourth active regions, wherein portions of the first and third active regions underlying the gate structure have a same height and same conductivity type, and portions of the second and fourth active regions underlying the gate structure have a same height and same conductivity type.
18. The method of claim 17 , wherein the channel region is also located along a top portion and sidewall portions of the third active region adjacent the gate structure.