FinFET power supply decoupling

摘要

Embodiments herein describe dummy gates disposed over a portion of a fin in finFETs. That is, instead of separating the dummy gates from the finFET structure, the fins may be extended and covered, at least partially, by the dummy gates. An insulative material is disposed between the dummy gate and the fin in order to form a decoupling capacitor. In one embodiment, the dummy gate overlaps a portion of the fin that is held at a voltage rail. Moreover, the dummy gate may be coupled to a different (e.g., opposite) voltage rail than rail coupled to the fin. For example, if the fin is coupled to VHIGH then the dummy gate is coupled to VLOW, or vice versa. Thus, the capacitor formed using the fin and the dummy gate provides a decoupling capacitance between the power sources generating the voltage rails (i.e., VHIGH and VLOW).

主权项

1. A fin field effect transistor (FET) comprising:
a fin extending in a first direction on a substrate; a gate extending in a second direction on the substrate substantially perpendicular to the first direction, wherein the gate is disposed over a first portion of the fin in order to selectively activate a conductive channel in the first portion of the fin in response to a time-varying gate signal; a dummy fin structure extending in the second direction on the substrate and overlapping a second portion of the fin, wherein the dummy fin structure is coupled to a first voltage rail; a conductive contact contacting a third portion of the fin located between the first and second portions, the contact electrically coupling the third portion of the fin to a second voltage rail different from the first voltage rail; and a dielectric material disposed between the dummy fin structure and the second portion of the fin, whereby the dielectric material and second portion of the fin form a decoupling capacitance between the first and second voltage rails.