FABRICATION AND STRUCTURE OF ASYMMETRIC FIELD-EFFECT TRANSISTORS USING L-SHAPED SPACERS

摘要

Fabrication of an asymmetric field-effect transistor (102) entails defining a gate electrode (302) above, and vertically separated by a gate dielectric layer (300) from, a channel-zone portion (284) of body material of a semiconductor body. Semiconductor dopant is introduced into the body material to define a more heavily doped pocket portion (290) using the gate electrode as a dopant-blocking shield. A spacer (304T) is provided along the gate electrode. The spacer includes (i) a dielectric portion situated along the gate electrode, (ii) a dielectric portion situated along the semiconductor body, and (iii) a filler portion (SC) largely occupying the space between the other two spacer portions. Semiconductor dopant is introduced into the semiconductor body to define a pair of main source/drain portions (280M and 282M) using the gate electrode and the spacer as a dopant-blocking shield. The filler spacer portion is removed to convert the spacer to an L shape (304). A pair of electrical contacts (310 and 312) are formed respectively to the main source/drain portions.