Reliability in mergeable semiconductor devices

1. A method of fabricating a transistor device having a channel of a first conductivity type formed during operation in a body region having a second conductivity type, the method comprising:

forming a first well region of the body region in a semiconductor substrate;

performing a first implantation procedure to counter-dope the first well region with dopant of the first conductivity type to define a second well region of the body region, the first implantation procedure being configured to establish a net conductivity of the second conductivity type for the second well region; and

performing a second implantation procedure to form a source region in the first well region and a drain region in the second well region.

2. The method of claim 1 , further comprising:

performing a third implantation procedure to implant dopant of the first conductivity type in the semiconductor substrate to form a drain extension region adjacent the drain region; and

performing a fourth implantation procedure to implant dopant of the second conductivity type to form a pocket in the drain extension region to establish a depletion region along an edge of the drain region.

3. The method of claim 2 , wherein the fourth implantation procedure is configured to form a source/drain extension region of a power field-effect transistor (FET) device in the semiconductor substrate.

4. The method of claim 2 , wherein the third and fourth implantation procedures are configured to form respective source/drain extension regions of power field-effect transistor (FET) devices in the semiconductor substrate.

5. The method of claim 2 , wherein the pocket is disposed at a surface of the semiconductor substrate.

6. The method of claim 1 , wherein the first implantation procedure is configured to form an accumulation region of a power field-effect transistor (FET) device in the semiconductor substrate.

7. The method of claim 1 , wherein:

the transistor device is a first transistor device of a plurality of transistor devices;

performing the first implantation procedure is configured to further define a third well region of the body region, the third well region being associated with a second transistor device of the plurality of transistor devices; and

performing the second implantation procedure is configured to form a further source region in the first well region and a further drain region in the third well region, the further source and drain regions being associated with the second transistor device.

8. The method of claim 7 , further comprising forming an isolation ring that defines an active area in which the transistor device is disposed, wherein the first well region extends across an entire lateral extent of the active area to abut the isolation ring.

9. The method of claim 1 , wherein:

forming the first well region comprises performing a fifth implantation procedure to implant dopant of the second conductivity type in the semiconductor substrate; and

the fifth implantation procedure is configured to establish, at a surface of the semiconductor substrate, a concentration level of the dopant of the second conductivity type less than one order of magnitude greater than a concentration level of the dopant of the first conductivity type implanted by the first implantation procedure.

10. A method of fabricating a transistor device having a channel of a first conductivity type formed during operation in a body region having a second conductivity type, the method comprising:

forming an isolation ring that defines an active area in which the transistor device is disposed;

forming a first well region of the body region in a semiconductor substrate, the first well region extending across an entire lateral extent of the active area to abut the isolation ring;

performing a first implantation procedure to counter-dope the first well region with dopant of the first conductivity type to define a second well region of the body region, the first implantation procedure being configured to establish a net conductivity of the second conductivity type for the second well region; and

performing a second implantation procedure to form a source region in the first well region and a drain region in the second well region.

11. The method of claim 10 , further comprising:

performing a third implantation procedure to implant dopant of the first conductivity type in the semiconductor substrate to form a drain extension region adjacent the drain region; and

performing a fourth implantation procedure to implant dopant of the second conductivity type to form a pocket in the drain extension region to establish a depletion region along an edge of the drain region.

12. The method of claim 11 , wherein the fourth implantation procedure is configured to form a source/drain extension region of a power field-effect transistor (FET) device in the semiconductor substrate.

13. The method of claim 10 , wherein the first implantation procedure is configured to form an accumulation region of a power field-effect transistor (FET) device in the semiconductor substrate.

14. The method of claim 10 , wherein the transistor device is a first transistor device of a plurality of transistor devices disposed within the active area, each transistor device of the plurality of transistor devices having respective regions formed by the first and second implantation procedures.

15. The method of claim 10 , wherein:

forming the first well region comprises performing a fifth implantation procedure to implant dopant of the second conductivity type in the semiconductor substrate; and

the fifth implantation procedure is configured to establish, at a surface of the semiconductor substrate, a concentration level of the dopant of the second conductivity type less than one order of magnitude greater than a concentration level of the dopant of the first conductivity type implanted by the first implantation procedure.

16. A method of fabricating a transistor device having a channel of a first conductivity type formed during operation in a body region having a second conductivity type, the method comprising:

forming a first well region of the body region in a semiconductor substrate;

performing a first implantation procedure to counter-dope the first well region with dopant of the first conductivity type to define a second well region of the body region, the first implantation procedure being configured to establish a net conductivity of the second conductivity type for the second well region;

performing a second implantation procedure to form a source region in the first well region and a drain region in the second well region;

performing a third implantation procedure to implant dopant of the first conductivity type in the semiconductor substrate to form a drain extension region adjacent the drain region; and

performing a fourth implantation procedure to implant dopant of the second conductivity type to form a pocket in the drain extension region to establish a depletion region along an edge of the drain region.

17. The method of claim 16 , wherein the first implantation procedure is configured to form an accumulation region of a power field-effect transistor (FET) device in the semiconductor substrate.

18. The method of claim 16 , wherein:

the transistor device is a first transistor device of a plurality of transistor devices;

performing the first implantation procedure is configured to further define a third well region of the body region, the third well region being associated with a second transistor device of the plurality of transistor devices; and

performing the second implantation procedure is configured to form a further source region in the first well region and a further drain region in the third well region, the further source and drain regions being associated with the second transistor device.

19. The method of claim 18 , further comprising forming an isolation ring that defines an active area in which the transistor device is disposed, wherein the first well region extends across an entire lateral extent of the active area to abut the isolation ring.

20. The method of claim 16 , wherein:

forming the first well region comprises performing a fifth implantation procedure to implant dopant of the second conductivity type in the semiconductor substrate; and

the fifth implantation procedure is configured to establish, at a surface of the semiconductor substrate, a concentration level of the dopant of the second conductivity type less than one order of magnitude greater than a concentration level of the dopant of the first conductivity type implanted by the first implantation procedure.