The assignee ranking for this dataset is topped by a single applicant holding 249 of 2,169 records, with a steep drop to 116 records at fifth place and 48 at tenth place. The five leading assignees together hold 36.6% of all records in scope, and the ten leading assignees hold 51.3%. This is a leader-and-long-tail structure: a handful of applicants set the claim boundaries that most others have to work around, and the remaining filers are spread thinly across the rest of the ranking.

Filing activity peaked at 106 records in 2020 and has since declined, with complete-year data showing a drop from 95 filings in 2021 to 47 in 2024 — a 51% fall over that span. However, records published in 2025 and 2026 are still incomplete because publication typically lags filing by roughly 18 months, so the most recent years understate real activity. The honest read is that the field cooled from its 2020 peak through 2024; whether it has continued to cool since then is not yet visible in this data.

Both appear as growth-route keywords within this dataset’s search scope, and both fall largely under the C30B crystal-growth IPC subclass, which covers 38.4% of the 2,169 records — notably less than the 79.8% covered by H01L device-structure claims. That gap suggests growth-process claims, including ammonothermal seed chemistry and HVPE flow-ratio control such as the technique in US10497562B1, are less densely claimed than the device architectures built on top of the resulting substrates. Anyone comparing the two routes for freedom-to-operate purposes should check growth-process claims specifically rather than relying on device-level searches.