Method of deposition of thin films of amorphous and crystalline microstructures based on ultrafast pulsed laser deposition
US6312768A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 21, 2000 |
| Grant date | Nov 6, 2001 |
| Priority date | — |
| Expiry date | Jun 21, 2020 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC23C14/0605
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
Powerful nanosecond-range lasers using low repetition rate pulsed laser deposition produce numerous macroscopic size particles and droplets, which embed in thin film coatings. This problem has been addressed by lowering the pulse energy, keeping the laser intensity optional for evaporation, so that significant numbers of the macroscopic particles and droplets are no longer present in the evaporated plume. The result is deposition of evaporated plume on a substrate to form thin film of very high surface quality. Preferably, the laser pulses have a repetition rate to produce a continuous flow of evaporated material at the substrate. Pulse-range is typically picosecond and femtosecond and repetition rate kilohertz to hundreds of megahertz. The process may be carried out in the presence of a buffer gas, which may be inert or reactive, and the increased vapour density and therefore the collision frequency between evaporated atoms leads to the formation of nanostructured materials of increasing interest, because of their peculiar structural, electronic and mechanical properties. One of these is carbon nanotubes, which is a new form of carbon belonging to the fullerene (C.sub.60) family. …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.