Method of creating asymmetric field-effect-transistors

Abstract

The present invention provides a method of forming asymmetric field-effect-transistors. The method includes forming at least a first and a second gate-mask stack on top of a semiconductor substrate, wherein the first and second gate-mask stacks include at least, respectively, a first and a second gate conductor of a first and a second transistor and have, respectively, a top surface, a first side, and a second side with the second side being opposite to the first side; performing a first halo implantation from the first side of the first and second gate-mask stacks at a first angle while applying the first gate-mask stack in preventing the first halo implantation from reaching a first source/drain region of the second transistor, wherein the first angle is equal to or larger than a predetermined value; and performing a second halo implantation from the second side of the first and second gate-mask stacks at a second angle, thereby creating halo implant in a second source/drain region of the second transistor, wherein the first and second angles are measured against a normal to the substrate.