Method of making MIS-field effect transistor having a short channel length

Claim 1

A method for producing an MIS field effect transistor exhibiting a short channel length and having source and drain zones contacted by respective electrodes, and an insulating layer overlying an intermediate gate zone provided thereon with a gate-electrode, comprising the steps of: forming by known steps on a semiconductor member laterally spaced source and drain zones of a first conductivity type contacted by respective electrodes, and an insulating layer intermediate the source and drain zones upon which layer is disposed a gate electrode layer, with the source and drain zones extending from the contact surface into the semiconductor member; prior to the mounting of said source and drain electrodes, implanting into the semiconductor member dopant particles of the first conductivity type, utilizing as an implantation mask said insulating layer on said semiconductor member having edges overlapping the source zone and the drain zone, which edges have a beveled or wedge-shaped configuration, and so selecting the implantation energy and the implantation dose of such doping particles that a concentration maximum of the doping particles of the first conductivity type extends underneath the source and drain zones and therefrom obliquely to the substrate surface underneath the wedge-shaped edges of the implantation mask, and the zones formed thereby exhibiting a weaker doping than the source and drain zones per se; and implanting particles of the second conductivity type, utilizing the same implantation mask only in the area of the source zone, and so selecting the implantation energy and implantation dose that a concentration maximum of the doping particles of the second conductivity type extends under the concentration maximum of the doping particles of the first conductivity type and also extends obliquely to the semiconductor surface underneath the wedge-shaped edges of the implantation mask.

Claim 2

A method for producing an MIS field effect transistor exhibiting a short channel length and having source and drain zones contacted by respective electrodes, and an insulating layer overlying an intermediate gate zone provided thereon with a gate-electrode, comprising the steps of: forming by known steps on a semiconductor member laterally spaced source and drain zones of a first conductivity type contacted by respective electrodes, and an insulating layer intermediate the source and drain zones upon which layer is disposed a gate electrode layer, with the source and drain zones extending from the contact surface into the semiconductor member; prior to the mounting of said source and drain electrodes, implanting into the semiconductor member dopant particles of the first conductivity type, utilizing as an implantation mask said insulating layer on said semiconductor member having edges overlapping the source zone and the drain zone, which edges have a beveled or wedge-shaped configuration, and so selecting the implantation energy and the implantation dose of such doping particles that a concentration maximum of the doping particles of the first conductivity type extends underneath the source and drain zones and therefrom obliquely to the substrate surface underneath the wedge-shaped edges of the implantation mask, and the zones formed thereby exhibiting a weaker doping than the source and drain zones per se; and implanting particles of the second conductivity type, utilizing the same implantation mask only in the area of the source zone, and so selecting the implantation energy and implantation dose that a concentration maximum of the doping particles of the second conductivity type extends under the concentration maximum of the doping particles of the first conductivity type and also extends obliquely to the semiconductor surface underneath the wedge-shaped edges of the implantation mask.

Claim 7

A method according to claims 1, wherein the particles to be implanted with a concentration maximum extending deeper than the source or drain zones, are implanted with phosphorus at an acceleration energy of 180 through 300 keV.