Structure and electrical property of platinum film biased dc-sputter-deposited on silicon

Abstract A study is made by Cross-sectional transmission electron microscopy (X-TEM) and by measuring electrical resistivity ρ as a function of temperature (≦300 K), of structure and electrical property of Pt films equal to or thinner than 35 nm which are deposited on Si(0 0 1) at 200°C by dc-sputtering at −2.7 kV in Ar gas. A bias voltage Vs of 0 or −90 V is applied to the substrate during deposition. As deposited Pt films retain polycrystalline structure with PtSi compound formation and inter-atomic diffusion at the Pt/Si interface both of which are suppressed with application of Vs and the ρ values of them decrease with an increase in temperature T from 50–150 to 300 K depending on both Vs and thickness. After annealed at 450°C for 30 min in 10−5 Pa, the films consist mainly of PtSi at V s =0 V and still mainly of Pt at V s =−90 V while the T range where negative T coefficient of ρ (n-TCR) is observed is localized between 100 and 140 K for the 33 nm thick film prepared at V s =0 V but diffused away from 70 to 220 K for the 35 nm thick film prepared at V s =−90 V . The application of Vs is effective to determine the structural and electrical properties of Pt films dc-plasma-sputter deposited on Si(0 0 1) through controlling compound formation and inter-atomic diffusion at the interface.