Photoionization mass spectroscopy flux monitor
AssigneeThe United States of America as represented by the Secretary of Commerce
InventorsStephen R. Leone, Struppp Paul G., Russell V. Smilgys, April L. Alstrin
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Abstract
The present invention provides a photoionization mass spectroscopy flux monitor for gaseous species above a sample surface. It provides an in situ, real time, species specific, nonintrusive probe with a geometry compatible with conventional MBE growth chambers. Gaseous species are photoionized above a sample surface and the ionized gaseous species are extracted parallel to the sample surface and coupled into a mass spectrometer inlet adjacent to the sample surface. The geometry of the flux monitor allows for simultaneous coupling of a charged particle beam with the sample surface, for example for monitoring film growth with RHEED.
Claims28
A flux monitor for detecting gaseous species in front of a sample surface comprising:
- photoionizing means for ionizing said gaseous species;
- a mass spectrometer for analyzing the ionized gaseous species;
- and
- extraction means for extracting said ionized gaseous species in a direction approximately parallel to said sample surface, and for coupling said ionized gaseous species with said mass spectrometer, said extraction means capable of extracting ions proximate to said sample surface.
A method of monitoring the flux of gaseous species above sample surface comprising the steps of:
- photoionizing said gaseous species;
- extracting the ionized gaseous species, including the ionized gaseous species proximate to said sample surface, in a direction approximately parallel to said sample surface;
- coupling said ionized gaseous species into a mass spectrometer;
- and
- analyzing said ionized gaseous species with said mass spectrometer.
Dependencies are inferred from the claim text.