Thin-gate SiO/sub 2/ films formed by in situ multiple rapid thermal processing

A reliable method of forming very thin SiO/sub 2/ films (<10 nm) has been developed by rapid thermal processing (RTP) in which in situ multiple RTP sequences have been employed. Sub-10-nm-thick SiO/sub 2/ films formed by single-step RTP oxidation (RTO) are superior to conventional furnace-grown SiO/sub 2/ on the SiO/sub 2//Si interface characteristics, dielectric strength, and time-dependent dielectric-breakdown (TDDB) characteristics. It has been confirmed that the reliability of SiO/sub 2/ film can be improved by pre-oxidation RTP cleaning (RTC) operated at 700-900 degrees C for 20-60 s in a 1%HCl/Ar or H/sub 2/ ambient. The authors discuss the dielectric reliability of the SiO/sub 2/ films formed by single-step RTO in comparison with conventional furnace-grown SiO/sub 2/ films. The effects and optimum conditions of RTC prior to RTO on the TDDB characteristics are demonstrated. The dielectric properties of nitrided SiO/sub 2/ films formed via the N/sub 2/O-oxynitridation process are described.<
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