Fabrication of asymmetric field-effect transistors using l-shaped spacers

Abstract

A gate electrode () of a field-effect transistor () is defined above, and vertically separated by a gate dielectric layer () from, a channel-zone portion () of body material of a semiconductor body. Semiconductor dopant is introduced into the body material to define a more heavily doped pocket portion () using the gate electrode as a dopant-blocking shield. A spacer (T) having a dielectric portion situated along the gate electrode, a dielectric portion situated along the body, and a filler portion (SC) largely occupying the space between the other two spacer portions is provided. Semiconductor dopant is introduced into the body to define a pair of source/drain portions (M andM) using the gate electrode and spacer as a dopant-blocking shield. The filler spacer portion is removed to convert the spacer to an L shape (). Electrical contacts (and) are formed respectively to the source/drain portions.