A CFET stacks an n-type and a p-type transistor vertically in the same footprint, rather than placing them side by side, to keep transistor density scaling as planar area runs out. Because the two channels are built at different heights in the same stack, they often need different channel materials — for example a SiGe channel for one polarity and a silicon or 2D-material channel for the other — to get comparable mobility for both electrons and holes. Patent filings in this niche focus specifically on how to integrate those different materials into one stacked structure without damaging either channel during processing.

The most-cited record in this dataset, US20190172755A1, has 91 citations, well ahead of any other filing in the set, and its related grant US10685887B2 is separately cited 27 times. Both describe methods for incorporating multiple channel materials into a CFET device, which makes them a natural reference point for later filers. Beyond that anchor, filing is spread thinly across a small group of IDMs, foundries and semiconductor-equipment makers rather than concentrated behind one dominant portfolio holder.

Based on the tracked filings, no — the yearly count peaked at 5 families in 2022 and has not exceeded that since, giving a flat rather than rising curve. That said, patent publication typically lags actual filing by around 18 months, so the last one or two years in any such dataset will always look artificially quiet. The fair reading is that this is a small, plateaued niche whose near-term trajectory is not yet confirmed either way, rather than one in clear decline.

In this dataset, sub-areas like 2D semiconductor channel integration into stacked CFET structures, SiGe-to-III-V transition schemes, and gate-cut dielectric pairing for stacked CMOS show noticeably thinner dedicated claim coverage than the core multi-channel-material integration methods. A new filer targeting one of these branches would likely face less directly-blocking prior art than one filing squarely on the anchor patent's territory. Confirming that gap against the full unfiltered patent corpus, not just this search string, is a sensible next step before committing to a claim strategy.

Nine of the 13 tracked records were filed through the USPTO, three as PCT applications, and one at the EPO, so the US is clearly the primary filing venue in this niche. That skew means freedom-to-operate analysis should start with US claim scope, but it also means coverage outside the US — particularly in East Asian markets where much of the fabrication actually happens — may be comparatively thin in this specific dataset. Anyone relying on that apparent gap should verify it against broader search terms, since a narrow search string like this one can understate filings that use different terminology in non-US jurisdictions.