Patent ID: 7968921
Filing Date: 2011-06-28
Classification: H01L

Abstract:
1. A structure comprising a field-effect transistor provided along an upper surface of a semiconductor body having body material of a first conductivity type, the transistor comprising: a channel zone of the body material; first and second source/drain (“S/D”) zones situated in the semiconductor body along its upper surface, laterally separated by the channel zone, and doped with composite semiconductor dopant of a second conductivity type opposite to the first conductivity type such that the S/D zones are of the second conductivity type so as to form respective pn junctions with the body material; a gate dielectric layer overlying the channel zone; and a gate electrode overlying the gate dielectric layer above the channel zone, each S/D zone comprising a main S/D portion and a more lightly doped lateral S/D extension laterally continuous with the main S/D portion and extending laterally under the gate electrode such that the channel zone is terminated by the S/D extensions along the body's upper surface, the S/D extension of the second S/D zone being more lightly doped than the S/D extension of the first S/D zone, the dopant of the second conductivity type having a concentration that locally reaches a subsurface maximum concentration in each S/D extension, the maximum concentration of the S/D extension of the second S/D zone averagely occurring materially deeper below the body's upper surface than the maximum concentration of the S/D extension of the first S/D zone, a pocket portion of the body material more heavily doped than laterally adjacent material of the body material extending largely along only the first of the S/D zones and into the channel zone so as to cause the channel zone to be asymmetric with respect to the S/D zones.