Effusion cell and method for use in molecular beam deposition
US7402779B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 13, 2004 |
| Grant date | Jul 22, 2008 |
| Priority date | — |
| Expiry date | May 30, 2025 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC30B35/00
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
An MBE effusion cell is configured to produce an inverted temperature gradient; that is, the top surface of the melt is not cooler than the bottom surface of the melt. In one embodiment, the MBE effusion cell comprises a crucible having tip, central and base regions. First filaments are located laterally adjacent the tip region; second filaments are located laterally adjacent the central region; and third filaments are located laterally adjacent all three of the regions. The radial density of the number of the heater filaments is lower adjacent the base region than adjacent the tip or central regions. In another embodiment, further tailoring of the inverted temperature gradient is obtained by reducing the amount of insulation at the base of the crucible. In another embodiment, at least one heater filament extends substantially along the longitudinal axis of the crucible and is located adjacent its lateral wall. Dielectric annular spacers are located around the lateral wall and are distributed along the longitudinal axis. The spacers having a multiplicity of holes through which the filaments pass. The filaments and spacers are located within a gas-blocking enclosure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.