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:
May. 14, 1991
Filed:
Sep. 30, 1987
Graham K Hubler, Alexandria, VA (US);
Edward P Donovan, Annandale, VA (US);
Deborah Van Vechten, Baltimore, MD (US);
The United States of America as represented by the Secretary of the Navy, Washington, DC (US);
Abstract
An apparatus and method for producing films of silicon nitride whose index of refraction varies continuously with film depth by preselected amounts between n=3.9 and n=1.99. This is done by producing an amorphous film of silicon nitride, Si.sub.1-x N.sub.x, of pre-selected stoichiometry between x=0 and x=0.57. In a vacuum-chamber, a target substrate is exposed to vaporized silicon while being simultaneously bombarded with an ion beam of relatively high kinetic energy, ionized, nitrogen particles. The nitrogen embeds in the silicon film deposited on the substrate to form amorphous silicon nitride, the stoichiometry of which depends on the intensity of the ion beam. Instruments measure during the deposition the relative rate of arrival at the target for silicon and nitrogen, and, with pre-generated calibration data for the apparatus, enable an operator to selectively control the film's stoichiometry by controlling the ion beam's intensity response to the measured rate of silicon deposition.