The problem of uniformity of properties of 4H-SiC CVD films

Nonuniformities of electrical properties of 4H-SiC CVD films have been revealed using physicochemical reactions occurring upon introduction of radiation-induced structural defects. Primary knocked-on atoms and vacancies actively interact with impurities and defects of the starting material and thereby form the final system of radiation centers. The samples were irradiated with 900-keV electrons and 8-MeV protons at doses not leading to conductivity compensation (<7.5 x 1012 cm-2) and a dose of 6 x 1014 cm-2 causing deep compensation. Despite their area-averaging nature, capacitance methods demonstrated that characteristics of samples ∼3 mm in size are not identical. The nuclear spectrometry technique, which enables microprobing of samples, demonstrated individual behavior of separate parts of a film with areas of tens of square micrometers.