Granted Patent B2

US 7,491,605 · App. 11/225,429 · Granted Feb 17, 2009

Abstract

Claims (51)

1. A method for making a semiconductor structure of a memory device, comprising:

forming a first dopant region of a second conductivity type in a substrate of a first conductivity type;

forming a bipolar transistor, including forming a base region of the bipolar transistor, the base region being of the first conductivity type;

forming a second dopant region of the first conductivity type in the first dopant region, the second dopant region being more heavily doped than the first dopant region, the second dopant region being distinct and separate from the base region, said forming a second dopant region and said forming a base region of the bipolar transistor occur in a same step;

forming a gate dielectric atop the second dopant region;

forming a first gate conductor atop the gate dielectric;

forming a field-effect transistor, comprising forming a second gate conductor coupled to the first gate conductor;

wherein the second dopant region, the gate dielectric, and the first gate conductor form a capacitor.

2. The method of claim 1 , wherein the substrate is a p-substrate, the first dopant region is an n-well, and the second dopant region is a p-type region.

3. The method of claim 1 , further comprising:

forming a first contact region of the second conductivity type in the first dopant region, the first contact region being more heavily doped than the first dopant region;

forming a second contact region of the first conductivity in the second dopant region, the second contact region being more heavily doped than the second dopant region.

4. The method of claim 1 , wherein said forming a first gate conductor and said forming a second gate conductor comprise part of forming a same conducting trace.

5. The method of claim 1 , wherein said forming a field-effect transistor comprises:

forming a third dopant region of the first conductivity type in the substrate;

forming a second gate dielectric atop the third dopant region, wherein the second gate conductor is located atop the second gate dielectric;

forming a source region of the second conductivity type in the third dopant region; and

forming a drain region of the second conductivity type in the third dopant region.

6. The method of claim 5 , wherein the third dopant region is a p-well.

7. The method of claim 1 , wherein the said forming a field-effect transistor comprises:

forming a second gate dielectric atop the substrate, wherein the second gate conductor is located atop the second gate dielectric;

forming a source region of the second conductivity in the substrate; and

forming a drain region of the second conductivity in the substrate.

8. A method for making a semiconductor structure of a memory device, comprising:

forming a first dopant region of a second conductivity type in a substrate of a first conductivity type;

forming a second dopant region of the first conductivity type in the first dopant region, the second dopant region being more heavily doped than the first dopant region;

forming a gate dielectric atop the second dopant region;

forming a first gate conductor atop the gate dielectric, wherein the second dopant region, the gate dielectric, and the first gate conductor form a capacitor;

forming a field-effect transistor, comprising forming a second gate conductor coupled to the first gate conductor;

forming a first contact region of the second conductivity type in the first dopant region, the first contact region being more heavily doped than the first dopant region;

forming a second contact region of the first conductivity in the first dopant region, the second contact region being more heavily doped than the first dopant region;

forming a field implant region of the first conductivity in the first dopant region and coupling the second contact region and the second dopant region; and

forming a field oxide between the second contact region and the second dopant region, wherein the first gate dielectric and the first gate conductor overlay the field oxide so an end of the first gate conductor terminates above the field oxide.

9. The method of claim 8 , wherein the substrate is a p-substrate, the first dopant region is an n-well, and the second dopant region is a p-type region.

10. The method of claim 8 , wherein said forming a second dopant region comprises part of forming a base region of a bipolar transistor.

11. The method of claim 8 , further comprising:

forming a first contact region of the second conductivity type in the first dopant region, the

first contact region being more heavily doped than the first dopant region;

forming a second contact region of the first conductivity in the second dopant region, the

second contact region being more heavily doped than the second dopant region.

12. The method of claim 8 , wherein said forming a first gate conductor and said forming a second gate conductor comprise part of forming a same conducting trace.

13. The method of claim 8 , wherein said forming a field-effect transistor comprises:

forming a third dopant region of the first conductivity type in the substrate;

forming a second gate dielectric atop the third dopant region, wherein the second gate conductor is located atop the second gate dielectric;

forming a source region of the second conductivity type in the third dopant region; and

forming a drain region of the second conductivity type in the third dopant region.

14. The method of claim 13 , wherein the third dopant region is a p-well.

15. The method of claim 8 , wherein the said forming a field-effect transistor comprises:

forming a second gate dielectric atop the substrate, wherein the second gate conductor is located atop the second gate dielectric;

forming a source region of the second conductivity in the substrate; and

forming a drain region of the second conductivity in the substrate.

Assignments (9)