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

A study is made by Cross-sectional transmission electron microscopy (X-TEM) and by measuring electrical resistivity r as a function of temperature (2300 K), of structure and electrical property of Pt ®lms equal to or thinner than 35 nm which are deposited on Si(0 0 1) at 2008C by dc-sputtering at ÿ2.7 kV in Ar gas. A bias voltage Vs of 0 or ÿ90 V is applied to the substrate during deposition. As deposited Pt ®lms 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 r 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 4508C for 30 min in 10ÿ5 Pa, the ®lms consist mainly of PtSi at Vs ˆ 0V and still mainly of Pt at Vs ˆ ÿ90V while the T range where negative T coef®cient of r (n-TCR) is observed is localized between 100 and 140 K for the 33 nm thick ®lm prepared at Vs ˆ 0V but diffused away from 70 to 220 K for the 35 nm thick ®lm prepared at Vs ˆ ÿ90 V. The application of Vs is effective to determine the structural and electrical properties of Pt ®lms dc-plasma-sputter deposited on Si(0 0 1) through controlling compound formation and inter-atomic diffusion at the interface. # 2001 Elsevier Science B.V. All rights reserved