IGF::OT::IGF IN THIS PHASE I RESEARCH, ZECOAT CORPORATION WILL DEVELOP AN AFFORDABLE, LOW-STRESS SILICON CL…

Public award description

IGF::OT::IGF IN THIS PHASE I RESEARCH, ZECOAT CORPORATION WILL DEVELOP AN AFFORDABLE, LOW-STRESS SILICON CLADDING PROCESS WHICH IS SUPER-POLISHABLE FOR LARGE UVOIR MIRRORS. THE PROPOSED ION-ASSISTED EVAPORATION PROCESS IS DIRECTLY SCALEABLE TO SIC MIRRORS SEVERAL METERS IN DIAMETER. THE PROCESS IS BASED ON A NOVEL, LOW TEMPERATURE, ION-ASSISTED, EVAPORATION TECHNIQUE (IAD), WHEREBY THE COATING STRESS OF A SILICON FILM MAY BE MANIPULATED FROM COMPRESSIVE TO TENSILE, IN ORDER TO PRODUCE A NEAR-ZERO NET STRESS FOR THE COMPLETE LAYER. A CLADDING WITH LITTLE INTRINSIC STRESS IS ESSENTIAL TO MINIMIZE BENDING THAT WOULD OTHERWISE DISTORT THE FIGURE OF VERY LIGHTWEIGHT MIRRORS. CURRENT METHODS TO PRODUCE A POLISHABLE SILICON CLADDING UTILIZE CVD PROCESSES THAT PRODUCE HIGHLY STRESSED SI COATINGS. THE CURRENT PROCESSES REQUIRE HIGH-TEMPERATURES (HUNDREDS OF DEGREES CELSIUS) AND ARE NOT READILY SCALEABLE TO LARGE MIRRORS. CVD SI CLADDING IS CURRENTLY LIMITED TO MIRROR SUBSTRATES LESS THAN 1-METER IN DIAMETER. THE PROPOSED IAD PROCESS PRODUCES LITTLE HEAT, AND THE MIRROR SIZE IS LIMITED ONLY BY THE SIZE OF THE VACUUM CHAMBER. LARGE SILICON CARBIDE (SIC) MIRRORS (3-4 METERS IN DIAMETER) ARE BEING CONSIDERED FOR FUTURE SPACEBASED UVOIR ASTRONOMY MISSIONS. THESE LIGHTWEIGHT MIRRORS WILL LIKELY REQUIRE A HIGHLY-POLISHABLE LAYER OF SILICON (10 TO 50 MICRONS) APPLIED ON TOP OF THE SIC. A RELATIVELY THICK LAYER OF SI IS DESIRABLE FOR THE PURPOSE OF REDUCING FIGURING TIME AND FOR ACHIEVING A SUPER-POLISHED SURFACE, SUITABLE FOR UV ASTRONOMY. NORMAL INCIDENCE 4-METER CLASS UVOIR TELESCOPES HAVE BEEN CITED AS A HIGH PRIORITY BY MULTIPLE GOVERNMENT REVIEW PANELS INCLUDING; THE NATIONAL RESEARCH COUNCIL'S (NRC) STUDY OF NASA'S SPACE TECHNOLOGY ROADMAP AND PRIORITIES, THE OFFICE OF THE CHIEF TECHNOLOGIST, THE COSMIC ORIGINS PROGRAM AND NWNH DECADAL.