Ultra-thin poly-crystalline TiN films grown by HiPIMS on MgO(100) — In-situ resistance study of the initial stage of growth

Abstract

The growth of ultra-thin TiN films on single-crystalline MgO(100) substrates by high power impulse magnetron sputtering (HiPIMS) was studied for growth temperatures ranging from 35°C to 600°C. X-ray analysis showed that the films had a textured poly-crystalline structure. Films grown by dc magnetron sputtering (dcMS) were epitaxial at the higher growth temperatures. In-situ resistance measurements, during growth, revealed the coalescence thickness and film continuity thickness. The film grown by HiPIMS at room temperature coalesced at 1.2±0.1nm and became structurally continuous at 2.67±0.15nm. At 600°C, the coalescence and continuity thicknesses decreased to 0.56±0.05nm and 0.82±0.05nm, respectively. X-ray reflectivity measurements revealed that the growth rate of the films was roughly constant for all growth temperatures. The film density increased slightly with growth temperature up to 5.3g/cm3 at 600°C and the surface roughness of the films decreased from 1nm to 0.3nm while the growth temperature increased from 35°C to 600°C. Grazing incident X-ray diffraction measurements showed the presence of [111], [200] and [220] crystallites at all growth temperatures. The smallest [200] and [220] grain sizes appeared at 100°C while the [200] grain size increased by increasing the growth temperature.