Patent ID: 8709883

Claim:
A method for forming a semiconductor structure, the method comprising: performing a first implant into a semiconductor substrate to form a well in which a plurality of transistors of a same conductivity type will be formed, wherein each transistor of a first subset of the plurality of transistors to be formed has a transistor width that satisfies a predetermined width constraint and each transistor of a second subset of the plurality of transistors to be formed has a transistor width that does not satisfy the predetermined width constraint, and wherein the first subset and the second subset are mutually exclusive; performing a second implant into the semiconductor substrate such that the second implant enters the semiconductor substrate at locations in the well in which transistors of the first subset of the plurality of transistors will be formed and does not enter the semiconductor substrate at locations in the well in which transistors of the second subset of the plurality of transistors will be formed, wherein the performing the second implant comprises implanting a dopant having a conductivity type opposite a conductivity type of a dopant implanted during the first implant; and forming the plurality of transistors in the well, wherein a channel region of each transistor of the first subset of the plurality of transistors is formed in a portion of the semiconductor substrate which received the second implant and a channel region of each transistor of the second subset of the plurality of transistors is formed in a portion of the semiconductor substrate which did not receive the second implant.