The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 25, 2000
Filed:
Sep. 15, 1998
Arto K Salokatve, Tampere, FI;
David C Poole, Horsham, GB;
Coherent, Inc., , US;
VG Systems Limited, Santa Clara, CA (US);
Abstract
An effusion cell (22) including a crucible (28) is configured such that when attached to the MBE apparatus at a predetermined distance from a rotatable substrate holder (24), a longitudinal axis (32) of the crucible is directed toward the substrate holder at an angle to the rotation axis (26) of the substrate holder. The crucible is heatable for melting a material (36) placed therein, the molten material forming a melt surface (38) from which molecules of the material are evaporated. The top of the crucible has an elliptical opening (31), the plane of which is parallel to the substrate holder. The crucible and the opening therein are configured such that a substrate (25) in the substrate holder receives only evaporated molecules which proceed directly thereto from the melt surface, through the opening. The evaporated molecules received by the substrate are contributed from an area of the melt surface which increases in proportion to the square of the distance of the melt surface from the substrate holder, as that distance increases due to depletion of the material in the crucible by evaporation. This provides that molecular flux on the substrate remains constant during the depletion.