Structural and physical analysis on MOCVD Ti–Si–N films

Abstract

Thin TiSiN flat films deposited by MOCVD have been analysed in order to evaluate their microstructure and physical properties. TEM, XRR and RBS techniques have been utilised as complementary analyses to evaluate thickness, density and composition. The main composition is Ti : N : Si = 0.9 : 1.1 : 0.14 with carbon and oxygen up to 5% as a result of organic residuals and oxidation. The analysis shows a layered structure which well correlates with deposition steps. TiN nanocrystals embedded in a SiN x -rich amorphous matrix result confined into each TiSiN deposited layer. The silane soak produces a low concentration silicon inclusion, mainly stabilising the grain boundaries and not affecting the TiN crystalline morphology. AES profiles show that the TiSiN film consists of Ti–N rich layers, separated by C and Si rich “interface” layers which are the result of the process sequence. Densification and crystallisation of the film were observed after high temperature annealing in vacuum, resulting in an electrical resistivity decrease. PECVD deposition of an oxide layer on TiSiN causes a strong oxidation and resistivity increase of the film.