ESCA compositional profiles and electrical properties of diamond‐like carbon film/Si MIS structure

Abstract Diamond‐like carbon (DLC) films were deposited on silicon wafers by hydrogen gas reactive dc‐sputtering of graphite and fabricated MIS diodes. ESCA chemical depth profiles showed that almost no impurities such as oxygen and nitrogen were present in the bulk of DLC films. In the interfacial region between DLC and Si substrate, a small amount of Si‐C bonding as well as natural oxide of silicon were detected. It is found that the 1st‐derivative spectrum of C‐KLL Auger line in ESCA from the DLC film surface was very similar to the C‐KLL AES spectrum from natural diamond. This suggests that DLC film has a fairly diamond‐like tetrahedral sp 3 C‐C bonding configuration. The C‐V curves of the Hg/DLC/Si MIS diodes showed accumulation, depletion and inversion characteristics. The charge trapped in DLC film and the interface state density distribution as a function of the surface potential were obtained first. Both the amount of trapped charge and the C‐V hysteresis were considerably smaller compared to an Si 3 N 4 /Si diode. The interface state density curve exhibits a “U” shape and the minimum density was less than 3 × 10 10 /cm 2 /eV in the vicinity of the mid‐band gap.

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