Tellurium-carbon (TeC:H) films for a write-once read many (WORM) optical disk memory

Abstract

A tellurium-carbon (TeC:H) film was deposited by the reactive sputtering of a Te target in an atmosphere containing methane. Raman spectroscopy. X-ray photoelectron spectroscopy (XPS), and FT-IR absorption spectroscopy have shown that the chemical state of carbon in the TeC:H film is not amorphous carbon but rather sp 3-hybridized hydrocarbon. Thermal decomposition of the TeC:H film produced sp 2-hybridized hydrocarbon gas, which was analyzed by FT-IR/TG (thermogravimetry) measurements. Raman and FT-IR spectroscopies have supported the view that the structure of the TeC:H film is a composite structure consisting of amorphous tellurium and hydrocarbon fragments produced in methane plasma. The ablative optical recording sensitivity of the TeC:H film has been confirmed to be superior to that of a Te film, and its long archival and shelf lives have been recognized by accelerated aging tests. The recording sensitivity of the co-sputtered film consisting of tellurium and graphite carbon was found to be insufficient compared with the sensitivity of the Te film.