Integrated circuits with varying gate structures and fabrication methods

摘要

Integrated circuits and fabrication methods are provided. The integrated circuit includes: a varying gate structure disposed over a substrate structure, the varying gate structure including a first gate stack in a first region of the substrate structure, and a second gate stack in a second region of the substrate structure; a first field-effect transistor in the first region, the first field-effect transistor including the first gate stack and having a first threshold voltage; and a second field-effect transistor in the second region, the second field-effect transistor including the second gate stack and having a second threshold voltage, where the first threshold voltage is different from the second threshold voltage. The methods include providing the varying gate structure, the providing including: sizing layer(s) of the varying gate structure with different thickness(es) in different region(s).

主权项

1. A device comprising:
an integrated circuit, the integrated circuit comprising:
a varying gate structure disposed over a substrate structure, the varying gate structure comprising a first gate stack in a first region of the substrate structure, a second gate stack in a second region of the substrate structure, a third gate stack in a third region of the substrate structure, and a fourth gate stack in a fourth region of the substrate structure, wherein the first gate stack, second gate stack, third gate stack and fourth gate stack are different gate stacks;a first field-effect transistor in the first region of the substrate structure, the first field-effect transistor comprising the first gate stack of the varying gate structure and having a first threshold voltage; anda second field-effect transistor in the second region of the substrate structure, the second field-effect transistor comprising the second gate stack of the varying gate structure and having a second threshold voltage, wherein the first threshold voltage is different from the second threshold voltage,a third field-effect transistor in the third region of the substrate structure, the third field-effect transistor comprising the first gate stack of the varying gate structure and having a third threshold voltage different than the first and second threshold voltages; anda fourth field-effect transistor in the fourth region of the substrate structure, the fourth field-effect transistor comprising the fourth gate stack of the varying gate structure and having a fourth threshold voltage that is different from the first, second and third threshold voltages, wherein the first gate stack and the second gate stack of the varying gate structure comprises a gate dielectric layer, a first cap layer overlying the gate dielectric layer, a second cap layer overlying the first cap layer, a first work-function layer overlying the second cap layer, and a metal layer overlying the second work function layer, wherein the second cap layer has a first thickness in the first gate stack and a second thickness in the second gate stack that is different from the first thickness, wherein the first gate stack and the second gate stack of the varying gate structure comprises the layers of the first and second gate stacks and a second work function layer positioned between the second conductive cap layer and the first work function layer, and wherein the second cap layer has the first thickness in the third gate stack and the second thickness at the fourth gate stack, and wherein the second work function layer has a first thickness in the third gate stack and a second thickness in the fourth gate stack that is different from the first thickness.