Inverted cross-couple for top-tier fet for multi-tier gate-on-gate 3di

Abstract

Aspects of the present disclosure provide a multi-tier semiconductor structure. For example, the semiconductor structure can include a lower semiconductor device tier including lower semiconductor devices, an upper semiconductor device tier disposed over the lower semiconductor device tier and including upper semiconductor devices, a separation layer disposed between and separating the lower and upper semiconductor device tiers, a wiring tier disposed below the lower semiconductor device tier, a lower gate contact extending from a lower gate region of the lower semiconductor device tier downward to the wiring tier, an upper gate contact extending from an upper gate region of the upper semiconductor device tier downward through the separation layer to the wiring tier, and an isolator covering a lateral surface of the upper gate contact and electrically isolating the upper and lower gate contacts. The lower gate contact and the upper gate contact can be independent from each other.