US Patent 11038040 Fin field effect transistor devices with robust gate isolation

A method of forming a complementary metal oxide semiconductor (CMOS) device is provided. The method includes forming a plurality of vertical fins on a substrate, and forming at least two dummy gates across the plurality of vertical fins. The method further includes forming a masking block on one of the at least two dummy gates, and removing the portions of the at least two dummy gates not covered by the masking block, wherein the portion of the one dummy gate covered by the masking block forms a dummy gate plug. The method further includes forming a gate dielectric layer on the exposed surfaces of the plurality of vertical fins and dummy gate plug, and forming a conductive gate layer on the gate dielectric layer, wherein the dummy gate plug physically separates two active gate structures.