Structure and method for hyper-abrupt junction varactors
AssigneeInternational Business Machines Corporation
InventorsDouglas COOLBAUGH, Stephen FURKAY, Jeffrey JOHNSON, Robert RASSEL, David SHERIDAN
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Abstract
Method of fabricating a varactor that includes providing a semiconductor substrate, doping a lower region of the semiconductor substrate with a first dopant at a first energy level, doping a middle region of the semiconductor substrate with a second dopant at a second energy level lower than the first energy level, and doping an upper region of the semiconductor substrate with a third dopant at a third energy level lower than the second energy level.
Claims14
A method of fabricating a varactor, comprising:
- providing a semiconductor substrate;
- doping a lower region of the semiconductor substrate with a first dopant at a first energy level;
- doping a middle region of the semiconductor substrate with a second dopant at a second energy level lower than the first energy level;
- and
- doping an upper region of the semiconductor substrate with a third dopant at a third energy level lower than the second energy level.
A method of fabricating a varactor, comprising:
- doping a lower region of a substrate layer with a first dopant having a dopant profile such that atoms having a first energy (“A”) penetrate to a first depth (“A′”) in the substrate layer forming a cathode and atoms having a second energy (“B”) penetrate to a second depth (“B′”) in the substrate layer forming a collector region above the cathode, wherein A>B and A′>B′;
- doping a middle region of the substrate layer with a second dopant, the middle region being tailored for an implant profile that forms an anode, the second dopant overlapping the collector region;
- and
- doping an upper region of the substrate layer with a source/drain type implant to form the anode,
- wherein the doping of the middle region has approximately less energy than the doping of the lower region and the doping of the upper region has approximately less energy than the doping of the middle region.
A method of fabricating a varactor, comprising:
- forming a semiconductor substrate;
- doping a lower region of the semiconductor substrate with a first dopant at a first energy level;
- doping a middle region of the semiconductor substrate with a second dopant at a second energy level lower than the first energy level;
- and
- doping an upper region of the semiconductor substrate with a third dopant at a third energy level lower than the second energy level,
- wherein the semiconductor substrate includes a collector region and a cathode that are formed in a single doping step via energy distribution of a single dopant type.
Dependencies are inferred from the claim text.