Thin films
US7419903B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 13, 2005 |
| Grant date | Sep 2, 2008 |
| Priority date | — |
| Expiry date | Mar 8, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2221/1089
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Thin films are formed by formed by atomic layer deposition, whereby the composition of the film can be varied from monolayer to monolayer during cycles including alternating pulses of self-limiting chemistries. In the illustrated embodiments, varying amounts of impurity sources are introduced during the cyclical process. A graded gate dielectric is thereby provided, even for extremely thin layers. The gate dielectric as thin as 2 nm can be varied from pure silicon oxide to oxynitride to silicon nitride. Similarly, the gate dielectric can be varied from aluminum oxide to mixtures of aluminum oxide and a higher dielectric material (e.g., ZrO2) to pure high k material and back to aluminum oxide. In another embodiment, metal nitride (e.g., WN) is first formed as a barrier for lining dual damascene trenches and vias. During the alternating deposition process, copper can be introduced, e.g., in separate pulses, and the copper source pulses can gradually increase in frequency, forming a transition region, until pure copper is formed at the upper surface. Advantageously, graded compositions in these and a variety of other contexts help to avoid such problems as etch rate control, electromi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.