The ranked leaders hold a meaningful share of total filings: the top 5 assignees account for 1,285 of the 3,055 records in scope, or 42.1%, and the top 10 account for 1,689, or 55.3%. That leaves close to half the field spread across a long tail of the remaining ranked companies plus unranked filers. For a newcomer, this means the core sequencing and apparatus claims are dense, but there is still substantial white space outside the top 10’s immediate coverage.

Thermal ALD relies on sequential self-limiting surface reactions driven by heat alone, while plasma-enhanced ALD (PEALD) introduces a plasma step to drive one half-reaction, typically improving growth-per-cycle and lowering process temperature. In this dataset both routes are captured together under the same search terms, and the most-cited records include both a general ALD process-sequence patent and a dedicated plasma-enhanced apparatus patent, indicating the field treats them as closely related rather than as separate technology tracks. Filers choose between them based on thermal budget constraints on the substrate, which is why device-integration classes like H01L carry claims referencing both.

Patent applications are typically published around 18 months after filing, so any year within that window is structurally incomplete in a snapshot like this one. The 2026 figure of 19 filings is not a real drop-off; it is a partial count that will keep rising as those applications publish. The only trend figure safe to quote as a real comparison is 2021 to 2024, which shows a -28% move — years after 2024 should be read as still filling in.