Patent ID: 6599804
Filing Date: 2003-07-29
Classification: H01L

Abstract:
A method of fabricating a principal field-effect transistor from a semiconductor body having body material of a first conductivity type, the method comprising the steps of:introducing first semiconductor dopant of the first conductivity type into the body material; subsequently providing a gate electrode above, and vertically separated by gate dielectric material from, a portion of the body material intended to be a channel zone for the transistor such that the semiconductor body has an upper surface along which there is a location for a channel surface depletion region that extends into the channel zone during transistor operation, such that the first dopant of the first conductivity type reaches a maximum concentration below the location for the channel surface depletion region, and such that the maximum concentration of the dopant of the first conductivity type occurs more than 0.1 &mgr;m deep into the body material but not more than 0.4 &mgr;m deep into the body material; and subsequently performing both of (a) introducing second semiconductor dopant of the first conductivity type into at least the intended channel-zone portion of the body material and (b) introducing semiconductor dopant of a second conductivity type opposite to the first conductivity type into the semiconductor body to form a pair of source/drain zones of the second conductivity type laterally separated by the channel zone such that the second dopant of the first conductivity type has a concentration which, in the channel zone along the body's upper surface, longitudinally reaches a local surface minimum at a location between the source/drain zones.