Control of Crystalline Structure and Electrical Properties of TaSiN Thin Film Formed by Reactive RF-Sputtering

The crystalline structure, thermal stability, and electrical properties of TaN and TaSiN thin films formed by reactive RF-sputtering with a broad range of N and Si composition ratios were investigated. TaSiN with a Si/(Si+Ta) ratio less than 25% were crystalline, whereas that with a ratio more than 25% was amorphous, regardless of the N 2 partial pressure. The amorphous films exhibited excellent thermal stability with no crystallization up to 900°C. Crystalline films consisted of columnar grains with sizes ranging from 20–30 nm. Electrical resistivity showed a strong dependence on the Si and N composition ratios. However, amorphous films deposited at low N 2 partial pressure exhibited constant resistivity, regardless of the Si/Ta ratio. These results clarify that the crystalline structure and electrical resistivity of TaSiN films can be controlled by varying the Si and N composition ratios.