RuO 2 films by metal-organic chemical vapor deposition
- PDF / 494,242 Bytes
- 5 Pages / 576 x 792 pts Page_size
- 110 Downloads / 253 Views
Pure and conducting RuO 2 thin films were successfully deposited on Si, SiO 2 /Si, and quartz substrates at temperatures as low as 550 °C by a hot wall metal-organic chemical vapor deposition (MOCVD). Bis(cyclopentadienyl)ruthenium, Ru(C 5 H 5 ) 2 , was used as the precursor. An optimized MOCVD process for conducting RuO 2 thin films was established. Film structure was dependent on MOCVD process parameters such as bubbler temperature, dilute gas flow rates, deposition temperature, and total pressure. Either pure RuO 2 , pure Ru, or a RuO 2 + Ru mixture was obtained under different deposition conditions. As-deposited pure RuO 2 films were specular, crack-free, and well adhered on the substrates. The Auger electron spectroscopy depth profile showed good composition uniformity across the bulk of the films. The MOCVD RuO 2 thin films exhibited a resistivity as low as 60 /JLCI-cm. In addition, the reflectance of RuO 2 in the NIR region had a metallic character.
I. INTRODUCTION Ruthenium dioxide (RuO 2 ), a transition metal dioxide with rutile structure, has very interesting properties such as low resistivity (p = 46 / i d - c m ) and high thermodynamic stability which are the basis for a variety of applications. RuO 2 has been well known as a corrosion-resistant electrode for chlorine or oxygen evolution.1 In recent research, RuO 2 thin films have shown great promise in several different VLSI metallization schemes.2'3 In addition, we have recently shown that RuO 2 is a very good metallization contact for ferroelectric lead titanate zirconate (PZT) films.4 The use of RuO 2 reduced the lattice mismatch and work function difference at the interface, and consequently reduced the defect entrapment, loss of polarization, and improved fatigue lifetime.4 Furthermore, RuO 2 exhibits excellent diffusion barrier properties. Green et al. demonstrated that RuO2 is an effective diffusion barrier against interdiffusion of Al and Si to annealing temperatures as high as 600 °C.5 RuO 2 was also suggested as a buffer layer for YBCO superconducting thin film for reducing interdiffusion and improving nucleation of the proper phase.6 RuO 2 thin films for resistor applications have been well documented.7 RuO 2 thin films have been prepared to date mainly by using RF-reactive sputtering,2'3'67 although one paper on the MOCVD of RuO 2 film was reported.5 A problem associated with the sputtered films is high film stress. It was found that the intrinsic stress of each of the sputtered films was compressive on the order of GPa.2'8 On the other hand, MOCVD is a valuable alternative method a
)Author to whom all correspondence should be addressed.
2644 http://journals.cambridge.org
J. Mater. Res., Vol. 8, No. 10, Oct 1993 Downloaded: 31 May 2014
since it offers low cost, easy composition control, high deposition rate, excellent step coverage, and compatibility to large-scale processing. However, information on MOCVD of RuO 2 is very scarce. Only Green et al. have reported the preparation of MOCVD of RuO 2 and Ru thin films.5 In their studies, ef
Data Loading...
