Abstract: A method was achieved for making FET stacked gate electrode structures with improved sidewall profiles. These more vertical sidewalls improve the control tolerance of the gate electrode length (L.sub.eff) and improve the shape of the sidewall spacers for making more reliable metal contacts to the self-aligned source/drain contact areas. The method uses a stacked gate electrode layer having a TEOS oxide and a hard mask of silicon nitride on the gate electrode polysilicon layer. During patterning of the stacked gate electrode structure using a photoresist mask, the hard mask minimizes the buildup of a polymer on the TEOS oxide sidewall. This polymer would otherwise act as a masking material resulting in an abrupt step at the TEOS oxide/polysilicon interface when the polysilicon etch is completed. This results in improved gate electrode line length tolerance and much improved sidewall spacers that minimize electrical shorts between the metal source/drain contacts and the polysilicon gate electrodes.

Abstract: A method for forming an antifuse interconnect structure, for a one-time fusible link, to be used with field-programmable gate arrays, has been developed. The process features the use of an amorphous silicon layer, used as the antifuse layer, with the amorphous silicon layer protected by a thin barrier layer, during the patterning procedure. The protected antifuse layer results in a reproducible thickness, and thus reproducible pulsing voltages, needed for rupturing of the antifuse layer. Planarization of an underlying metal plug, via an insulator refill procedure, offers a smooth surface for the overlying antifuse layer.

Abstract: A process has been developed in which a capacitor structure can be simultaneously fabricated with NFET and PFET to be used in EEPROM, SRAM or DRAM cells. The process features the use of a silicon nitride layer, protecting an underlying capacitor dielectric layer from an oxidation ambient, presented during a subsequent NFET source and drain drive-in procedure.