Epitaxial Defect Patents: Who Leads, Where the Gaps Are 2026
- Concentrated but not locked up: the top five assignees hold 19.9% of the 292 records in scope, and the top ten hold 34.2% — real concentration alongside a long tail of single-filing entrants.
- Filing momentum has cooled from its 2021 level: a documented -65% change from 17 records in 2021 to 6 in 2024, the last year that can be treated as complete under normal publication lag.
- The technology footprint spans two distinct branches: semiconductor device and crystal-growth claims (H01L, C30B) sit alongside alloy and heat-treatment claims (C22C, C21D) inside the same search scope.
Filing growth compares 2021 (17 records) with 2024 (6) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 292 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
This landscape covers 292 records filed between 2015 and the 2026 data cut-off that combine an epitaxial defect or stacking fault reference with a specific process or quality-control concept — surface preparation, pre-bake condition, nucleation defect density, inspection method, yield correlation, or carbon and oxygen contamination. The scope spans two overlapping technology traditions: semiconductor device and crystal-growth claims concentrated in H01L and C30B, and alloy and heat-treatment claims concentrated in C22C and C21D.
Reading the two branches together matters because a claim search limited to semiconductor classes alone would miss the metallurgical alloy-composition art that shares the same defect-control vocabulary, and vice versa. Filing activity peaked in 2023 and has since cooled from its 2021 level, though the most recent one to two years in any patent dataset are always undercounted because publication lags actual filing by roughly 18 months.
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Filing trends and technology composition
The 292 records in scope span 2015 through the 2026 cut-off, with publication lag meaning the most recent one to two years are always undercounted at the point of any given data pull.
Filing activity by year
Filings ran from 19 in 2017 to a peak of 20 in 2023, with a documented -65% change from 2021 (17) to 2024 (6) — the last year in this window treated as complete under normal publication lag. Years after 2024 are still filling in and should not be read as a decline.
Technology composition by IPC subclass
H01L (semiconductor devices) leads at 40.8% of the 292 records, followed by C22C (alloys) at 29.1% and C30B (crystal growth) at 21.6%. Because records can carry multiple IPC classes, these shares add to more than 100% of the record total and should be read as overlapping technology footprints, not as a partition of the field.
Shares are the percentage of the 292 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Epitaxial Defect and Stacking Fault Control with Eureka
This page is one run against one query. Ask Eureka your own question about epitaxial defect and stacking fault control and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records in this landscape
EP2041330A2 — austenitic steel sheet composition for delayed-cracking resistance
An austenitic steel sheet excellent in resistance to delayed cracking, with a composition defined by weight-percent ranges on carbon, manganese, silicon, aluminium, sulphur, phosphorus and nitrogen, plus at least one alloying element chosen from vanadium, titanium, niobium, molybdenum or chromium.Filed 2009-04-01; assigned to ArcelorMittal; sits in the alloy/heat-treatment branch of this search scope rather than the semiconductor epitaxial-defect branch.
View full filing| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | JP2009256138A | Epitaxial silicon carbide single crystal substrate and its manufacturing method | 154 |
| 2 | US6335233B1 | Method for fabricating MOS transistor | 137 |
| 3 | JP2011121847A | SiC EPITAXIAL WAFER AND MANUFACTURING METHOD OF THE SAME | 95 |
| 4 | US7279115B1 | Method to reduce stacking fault nucleation sites and reduce V<sub>f </sub> drift in bipolar devices | 52 |
| 5 | JP2008294245A | Method of manufacturing epitaxial wafer, and epitaxial wafer | 49 |
| 6 | US20050064723A1 | Method To Reduce Stacking Fault Nucleation Sites And Reduce Forward Voltage Drift In Bipolar Devices | 48 |
| 7 | US20080153709A1 | High temperature superconductors having planar magnetic flux pinning centers and methods for making the same | 41 |
| 8 | US20130071643A1 | Silicon carbide substrate and method of manufacturing the same | 39 |
| 9 | US7018554B2 | Method to reduce stacking fault nucleation sites and reduce forward voltage drift in bipolar devices | 32 |
| 10 | CN107326246A | 一种高性能高熵合金及其加工方法 | 28 |
Citation counts inside this searched corpus skew toward older records and should be read as a signal of influence, not of current filing priority.
Patent titles are shown in the language they were filed in, not translated, so that each record stays verifiable against the original filing — a translated title will not match in Eureka or in any national register. Each row carries its publication number; clicking a row searches Eureka by that number.
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Three findings stand out once filing volume, citation weight and IPC composition are read together rather than in isolation.
A short leader group, then a long tail
The leader holds 16 records and the top five combined hold 58, or 19.9% of the 292 records in scope. The top ten reach 34.2%, meaning roughly two-thirds of the field sits with the remaining 90 ranked assignees.
A real drop, not yet a verdict on the field
Recorded filings fell from 17 in 2021 to 6 in 2024, the last year in this window treatable as complete. Publication lag means 2025-2026 figures will fill in later, so this should be read as the most recent confirmed trend, not the final word.
Two branches, not one field
H01L (semiconductor devices) covers 40.8% of records and C30B (crystal growth) 21.6%, while C22C (alloys) covers 29.1% and C21D (heat treatment) 18.8%. Records can carry multiple classes, so the field reads as two overlapping technology traditions rather than a single track.
Old SiC wafer art still anchors the field
The most-cited record in the corpus is a 2009-published SiC epitaxial substrate manufacturing method, followed closely by a MOS transistor fabrication method and a SiC epitaxial wafer manufacturing record. High citation counts here reflect age and influence inside this searched set, not current filing priority.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to epitaxial defect and stacking fault control, with the prior art for and against each one.
Who is filing, and where the field is still open
The ranking spans 100 companies counted by records, with concentration at the top and a long tail of single- or few-filing entrants below it.
A clear but not dominant leader
The top-ranked assignee holds 16 of the 292 records in scope, with the fifth-place holder at 10 and tenth place at 8 — a gradual taper rather than a single dominant player.
A wide field below the leaders
The top ten combined hold 34.2% of the 292 records, leaving the majority of documented activity spread across the remaining 90 ranked assignees, many of whom appear only once or twice in the dataset.
Leading assignees have gone quiet recently
Several of the higher-ranked assignees show zero filings in the latest recorded year, including one with a documented -100% year-on-year change. That does not remove their existing claim scope from force, but it does mean their positions are fixed rather than still expanding.
Collaboration is the exception, not the rule
Only 10 co-assignee pairs are recorded across the dataset, with the strongest pairing appearing 7 times. Most assignees in this field file independently rather than through joint ventures or research partnerships.
| Assignee | Recent year | YoY |
|---|---|---|
| Pohang Iron & Steel Co., Ltd. (POSCO) | 0 | — |
| Hyundai Steel Co., Ltd. | 0 | — |
| Wolfspeed, Inc. | 0 | — |
| Halliburton Energy Services, Inc. | 0 | -100% |
| TK Techno Consulting | 0 | — |
| Shin-Etsu Handotai Co., Ltd. | 0 | — |
| Central Research Institute of Electric Power Industry | 0 | — |
| Toshiba Corporation | 0 | — |
Where to take this analysis next
The dataset points to a few concrete follow-ups for a team deciding where to file or where to challenge existing claims.
Map the alloy and semiconductor branches separately
Because this scope spans both C22C/C21D alloy claims and H01L/C30B semiconductor claims, splitting the two branches before drafting a freedom-to-operate opinion avoids conflating unrelated prior art.
Run a branch-level search in EurekaRevisit 2025-2026 filing counts once they mature
The current -65% 2021-2024 figure is the most recent trend that can be treated as complete; publication lag means later years should be rechecked before drawing conclusions about current momentum.
Track filing trends in EurekaWatch the quiet leaders for renewed activity
Several top-ranked assignees show zero recent filings, which makes their existing claim scope a fixed rather than moving target — worth monitoring for licensing or challenge opportunities.
Set up assignee monitoring in EurekaCommon questions on epitaxial defect and stacking fault patents
In this dataset, a record qualifies if its text or claims reference an epitaxial defect or stacking fault alongside a specific process or inspection concept — surface preparation, pre-bake condition, nucleation defect density, an inspection method, yield correlation, or carbon and oxygen contamination control. This combination narrows the field to process- and quality-control-oriented filings rather than every crystal-growth patent in general. The 292 records in scope reflect that combined search logic, spanning both semiconductor (H01L, C30B) and metallurgical (C22C, C21D) IPC territory.
The ranking covers 100 companies counted by records, with the leader holding 16 records and the fifth-ranked assignee holding 10. The top five combined account for 58 records, or 19.9% of the 292 records in scope, and the top ten reach 34.2%, which shows real concentration at the top alongside a long tail of single- or few-filing entrants. This is not a top-50 or top-100 list in the sense of covering every filer — it is the full ranking the underlying data endpoint returns.
Filings ran from 19 in 2017 up to a peak of 20 in 2023, and the documented change from 2021 (17 records) to 2024 (6 records) is a -65% drop over that span. 2024 is the most recent year that can be treated as complete, because publication typically lags actual filing by around 18 months, so 2025 and 2026 figures in any pull will understate real activity and should not yet be read as continued decline. Anyone tracking this trend should revisit the 2025-2026 figures again once they mature.
Among the receiving offices tracked, the United States leads with 76 filings, followed by Japan at 57, the European Patent Office at 42, China at 31, South Korea at 26 and the WIPO PCT route at 17. This spread suggests filers are pursuing protection across multiple major semiconductor and materials markets rather than concentrating in a single jurisdiction, consistent with a field that touches both device manufacturing and materials supply chains.
EP2041330A2, assigned to ArcelorMittal and filed in 2009, claims an austenitic steel sheet with specific carbon and manganese weight-percent ranges chosen for resistance to delayed cracking. It sits in the metallurgical branch of this search scope (alloys and heat treatment) rather than the semiconductor epitaxial-defect branch, so it does not block claims built around SiC or silicon epitaxial wafer defect control, inspection methods, or nucleation defect density reduction. Anyone working in the semiconductor side of this landscape should treat it as adjacent prior art rather than a direct blocker.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.