Process for the production of a MIS field effect transistor having an adjustable, extremely short channel length

A process for the production of a metal-insulator-substrate MIS field effect transistor having an adjustable, extremely short channel length, comprising the steps of:

• providing a semiconductor substrate of first conductivity type;
• applying an insulating layer to a surface of the substrate, said insulating layer also serving as an implantation mask for implantation of a source and a drain zone, the insulating layer having at least one portion which is thicker than other portions of the layer and is impermeable to oncoming ions, the thicker portion having an etched edge;
• producing by ion implantation through thinner portions of the insulating layer a doped zone of second conductivity type;
• applying a gate electrode layer having substantially vertical edges on the thinner portions of the insulating layer;
• producing by ion implantation the source and drain zones of first conductivity type between the gate electrode and thicker portions of the insulating layer such that the source and drain zones are surrounded by the doped zone of second conductivity type at least in a direction of the drain zone and at a side of the source zone adjoining the substrate surface;
• and
• forming a channel zone of a given effective channel length by superimposing at least two implantation steps using dopant particles of second conductivity type with differing implantation energy and doses which set the effective channel length, said two implantation steps being applied by masking the drain zone and doping between the thicker portion of the insulating layer and the vertical edges of the gate electrode through the source zone into a portion of the doped zone of second conductivity type so as to form the effective channel length of the channel zone between the source zone and remaining portions of the doped zone of second conductivity type.