Method of fabricating semiconductor transistor devices with asymmetric extension and/or halo implants

Abstract

A method of fabricating semiconductor devices begins by providing or fabricating a device structure that includes a semiconductor material and a plurality of gate structures formed overlying the semiconductor material. The method continues by creating light dose extension implants in the semiconductor material by bombarding the device structure with ions at a non-tilted angle relative to an exposed surface of the semiconductor material. During this step, the plurality of gate structures are used as a first implantation mask. The method continues by forming a patterned mask overlying the semiconductor material, the patterned mask being arranged to protect shared drain regions of the semiconductor material and to leave shared source regions of the semiconductor material substantially exposed. Thereafter, the method creates heavy dose extension implants and/or halo implants in the semiconductor material by bombarding the device structure with ions at a tilted angle relative to the exposed surface of the semiconductor material, and toward the plurality of gate structures. During this step, the plurality of gate structures and the patterned mask are used as a second implantation mask.