Changes in Preferred Orientation of Pt Thin Films Deposited by dc Magnetron Sputtering Using Ar/O 2 Gas Mixtures
- PDF / 158,315 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 5 Downloads / 205 Views
MATERIALS RESEARCH
Welcome
Comments
Help
Changes in preferred orientation of Pt thin films deposited by dc magnetron sputtering using AryO2 gas mixtures Min Hong Kim, Tae-Soon Park,a) and Euijoon Yoonb) School of Materials Science and Engineering, Seoul National University, Seoul 151-742, Korea
Dong-Su Lee,c) Dong-Yeon Park,c) Hyun-Jung Woo,c) Dong-Il Chun, and Jowoong Hac) Advanced Materials Area, Tong Yang Central Laboratories, Yongin, Kyoungki 449-910, Korea (Received 3 September 1997; accepted 9 October 1998)
(200)-oriented Pt thin films were deposited on SiO2ySi substrates by dc magnetron sputtering using AryO2 gas mixtures. Oxygen incorporation into Pt films changed deposition rate, resistivity, stress, and preferred orientation of the films. Increase in film resistivity and decrease in tensile stress were presumed to be the results of the incorporated oxygen into grain boundaries, while the change of preferred orientation resulted from the oxygen incorporation into the Pt lattice. The preferential growth of (200) planes with less total strain energy from the incorporated oxygen resulted in strong (200) preferred orientation in Pt films.
I. INTRODUCTION
The need for oxide thin films with high dielectric constant for memory devices and piezoelectric applications has generated a significant interest in the ferroelectric oxide thin films.1 The kind and the quality of the bottom electrode materials for the oxide films significantly affect the quality of oxide films.2,3 Pt is one of the bottom electrode materials widely used for the oxide thin films because it is stable at subsequent oxidizing deposition conditions, and has a large work function for low leakage currents.4 Moreover, Pt films are known to provide better nucleation sites for high quality ferroelectric thin films.5 The problems associated with the Pt electrode are due to their poor adhesion to oxide substrates, formation of hillocks or pinholes, and the oxidation of adhesion layers between substrates and Pt.2 The ferroelectric device performance can be tailored by controlling the preferred orientation of ferroelectric thin films since their ferroelectric properties are anisotropic. The improved device performance of a ferroelectric random access memory (FRAM) and a pyroelectric infrared sensor was attributed to the c-axis oriented ferroelectric thin films.6–8 The c-axis oriented ferroelectric thin films were deposited on (200)-oriented Pt thin films. However, (100) MgO substrates were used instead, since (111)-oriented Pt thin films are usually deposited on SiO2ySi substrates.9,10 In this sense, (200)a)
Present address: Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139. b) e-mail: [email protected] c) Present address: Inostek, Inc., R. 37-205, Seoul National University, Seoul 151-742, Korea. J. Mater. Res., Vol. 14, No. 4, Apr 1999
http://journals.cambridge.org
Downloaded: 15 Mar 2015
oriented Pt thin films on Si substrates are beneficial to large area applications, s
Data Loading...
