CMOS compatible low-resistivity Al—Sc metal etch stop
US12034050B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 2, 2021 |
| Grant date | Jul 9, 2024 |
| Priority date | — |
| Expiry date | Feb 14, 2043 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/12764
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
An aluminum-scandium (Al—Sc) etch stop that is both CMOS compatible and highly conductive, and a method for forming the same are disclosed. The low volatility of Sc in Cl and strong covalent bond between Al—Sc leads to an increase in resistance to NaCl corrosion and makes it difficult to dry etch in Cl-based chemistries, resulting in an excellent etch stop material, especially when used in conjunction with an overlying aluminum nitride (AlN) or aluminum scandium nitride (AlScN) piezoelectric layer. When deposited at high deposition temperatures or when subsequently annealed at >600° C., the Al—Sc has a low resistivity, enabling corresponding device operation at temperatures up to at least 500° C. While Al3Sc is the preferred composition, Al1-xScx with x between 5 and 100 atomic percent provides many of these same benefits but comes at the cost of increased electrical resistivity and etch resistance with increasing Sc content due to Sc oxidation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.