In this 248-record dataset, the leading assignee holds 19 records, with the fifth-ranked assignee at 9 and the tenth at 7 — a gradual taper rather than one company dominating outright. The top 5 assignees combined account for 26.2% of all 248 records, and the top 10 account for 41.1%. That leaves a majority of filings spread across a long tail of manufacturers, component suppliers and university labs, so leadership in this field is real but not exclusive.

Filing volume rose from 15 records in 2017 to a peak of 26 in 2023, passing through 17 at the 2022 midpoint, which reads as flat-to-declining rather than accelerating. However, publication typically lags filing by roughly 18 months, so the most recent years in any such trend are understated by definition. Treat a drop in the final one or two years as incomplete data rather than a confirmed slowdown until later filings publish.

China is the leading receiving office in this dataset with 115 of the tracked records, ahead of the United States at 84. Europe (EPO), WIPO/PCT, the United Kingdom and India each account for single-digit-to-low-double-digit counts. This distribution reflects where IGBT manufacturing and R&D investment is currently concentrated, and it means a China-inclusive search is essential for any freedom-to-operate work in this space.

US7557386B2, assigned to Infineon Technologies Austria AG and published in 2009, covers a reverse-conducting IGBT with a substrate engineered into distinct carrier-lifetime zones — a reduced-lifetime zone, a first lifetime zone near the front side, and an intermediate lifetime zone near the back side. It sits among the more heavily cited records in this dataset, indicating it has shaped subsequent claim drafting in reverse-conducting IGBT structures specifically. It does not block IGBT designs generally, only approaches that read on its specific carrier-lifetime zoning claims; alternative lifetime-control methods and non-reverse-conducting architectures fall outside its scope.

The technology composition shows H01L (core semiconductor device structure) present in 99.2% of the 248 records, while power-conversion classification H02M appears in only 3.2%, and packaging-adjacent classes like adhesives and cleaning sit below 2%. That gap suggests power-conversion circuit integration and module packaging chemistry are comparatively under-claimed relative to the die structure itself. A first claim aimed at, for example, thermal interface material composition or short-circuit withstand control circuitry is more likely to clear prior art than another trench field-stop structural variant.