QUALCOMM Incorporated
Circuits employing adjacent low-k dummy gate to a field-effect transistor (FET) to reduce FET source/drain parasitic capacitance, and related fabrication methods

Abstract:

Circuits employing an adjacent low-k dummy gate to a field-effect transistor (FET) to reduce FET source/drain parasitic capacitance, and related fabrication methods. To reduce or mitigate an increase in the source/drain parasitic capacitance(s) of a FET, a dummy gate adjacent to an active gate of the FET is provided to have a low-k (i.e., low relative permittivity). In this manner, the relative permittivity (k) between the source/drain of the FET and an adjacent dummy gate and/or source/drain of another FET is reduced, thereby reducing the parallel plate capacitance of the FET(s). Reducing parasitic capacitance of the FET(s) may allow further reduced scaling of the circuit to offset or mitigate a lack of reduction or increase in parasitic capacitance as a result of reducing gate pitch in the circuit. As gate pitch is reduced in the circuit, it may not be possible to proportionally reduce gate size without sacrificing gate control.