At&t Bell Laboratories

American Telephone & Telegraph Co., At&t Bell Laboratories

American Telephone and Telegraph, Co.

David S Yaney

Kuo-Hua Lee

Chih-Yuan Lu

Kye H Oh

A gate electrode having an insulating top layer as well as insulating sidewall spacers permits the source and drain regions to be electrically contacted through windows directly above the source and drain regions formed in a window pad layer. There is a conducting layer, termed a window pad layer, over portions of these regions. Because of the insulating top layer and sidewall spacers on the gate, the window may be misaligned with respect to the source and drain regions, and maybe even closer to the gate than are these regions, but electrical contacts to these regions are still obtained. The window pad layer may also be used as sublevel interconnect.

Folded extended window field effect transistor

A gate electrode having an insulating top layer as well as insulating sidewall spacers permits the source and drain regions to be electrically contacted through windows directly above the source and drain regions formed in a window pad layer. The window pad layer may also be used as a sublevel interconnect.

Method for making folded extended window field effect transistor

A method of implanting ions into the sidewalls of isolation trenches is disclosed. The method utilizes a series of ion implants to produce concentrations of the ion, in most cases boron, along the depth of the trench. Since the ion concentration exhibits a Gaussian distribution function which tails off rapidly, the width of the trench is narrowed after the implantation to guarantee a sufficient boron concentration at the sidewalls of the trench. A layer of an insulating material is used to narrow the trench, where a conformal coating of the material will cover the sidewalls of the window and narrow the opening through the window. By increasing the boron doping in the sidewalls, the effects of boron segregation between the substrate and the isolation trench will be counteracted, thus eliminating the problem of creating an n-type inversion layer between the trench and the substrate.

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Bethlehem, PA, United States of America

David S Yaney