Patent ID: 7700453

Claim:
A method of fabricating a hyper-abrupt junction varactor, comprising: providing a semiconductor substrate; doping a lower region of the semiconductor substrate with a first dopant at a first energy level, wherein the doping of the lower region comprises doping a lower portion of the lower region with a higher concentration of the first dopant than an upper portion of the lower region, and wherein the lower and upper portions are formed in a single doping step via energy distribution; after the doping of the lower region, doping a middle region of the semiconductor substrate arranged above the lower region with a second dopant having a lower implant dosage than the first dopant and at a second energy level lower than the first energy level; and after the doping of the middle region, doping an upper region of the semiconductor substrate arranged above the middle region with a third dopant at a third energy level lower than the second energy level, wherein the method forms the hyper-abrupt junction varactor.