Growth rate monitor for molecular beam epitaxy
US4812650A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 15, 1988 |
| Grant date | Mar 14, 1989 |
| Priority date | — |
| Expiry date | Jul 15, 2008 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC30B23/02
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A light source with appropriate optics focusses light on the wafer surface during deposition, while a nearby collector is biased to collect photoemitted electrons from the growing surface. A pico ammeter can be used to convert the small oscillatory current detected to a substantial voltage signal which can be recorded or processed by computer or other sutiable device. The light must contain wavelengths at energies close to or greater than the energy of the photoemission threshold. The detected photoemitted electron signal has an oscillatory component occurring due to the growth of epitaxial layers. This oscillation has frequency 1/.tau., where .tau. is the monolayer accumulation time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.