Electrical and structural properties of SrTiO 3 thin films deposited by plasma-enhanced metalorganic chemical vapor depo
- PDF / 207,112 Bytes
- 5 Pages / 612 x 792 pts (letter) Page_size
- 64 Downloads / 243 Views
MATERIALS RESEARCH
Welcome
Comments
Help
Electrical and structural properties of SrTiO3 thin films deposited by plasma-enhanced metalorganic chemical vapor deposition Nam-Kyeong Kim and Soon-Gil Yoon Department of Material Engineering, College of Engineering, Chungnam National University, Daeduk Science Town, 305-764, Taejon, Korea
Won-Jae Lee and Ho-Gi Kim Department of Ceramic Science & Engineering, Korea Advanced Institute of Science and Technology, Taejon, Korea (Received 18 November 1995; accepted 26 September 1996)
The microstructure and electrical properties were investigated for SrTiO3 (STO) thin films deposited on PtyTiySiO2ySi substrates by PEMOCVD. The SrF2 phase existing in the STO films deposited at 450 ±C influences the dielectric constant, dissipation factor, and leakage current density of STO films. The dielectric constant and dissipation factor of STO films deposited at 500 ±C were 210 and 0.018 at 100 kHz, respectively. STO films were found to have paraelectric properties from the capacitance-voltage characteristics. Leakage current density of STO films at 500 ±C was about 1.0 3 1028 Aycm2 at an electric field of 70 kVycm. The leakage current behaviors of STO films deposited at 500 and 550 ±C were controlled by Schottky emission with applied electric field.
I. INTRODUCTION
Recently, ferroelectric thin films have been investigated for application to integrated memory devices. For the increase of the integration density of dynamic random access memories (DRAM’S),1,2 high dielectric constant materials are required to obtain large charge storage density. Among numerous ferroelectric materials, paraelectric SrTiO3 has attracted particular attention because of its high dielectric constants and good thermal stability. Large area fabrication is a key issue for development of perovskite thin films. Metalorganic chemical vapor deposition (MOCVD) and plasma-enhanced metalorganic chemical vapor deposition (PEMOCVD) have been employed to deposit high quality perovskite thin films. The success of any MOCVD process depends critically on the volatility and stability of the precursor material. Until recently, complex strontium oxides have been prepared by Sr(dpm)2 (dpm: dipivaloylmethanate; C11 H19 O2 ) as Sr source.3–5 Sr(dpm)2 used for complex strontium oxides has many disadvantages such as the decreased volatilities of the source by repeated thermal cycling near the melting temperature of Sr(dpm)2 . Therefore, Sr(hfa)2 (tetraglyme) (hfa: hexafluoroacetylacetonate; C5 HF6 O2 ) which exhibits significantly improved volatility and vapor pressure stability was used in this study. However, Wills et al.6 have reported that the fluoride phase (BaF2 ) in BaTiO3 film deposited using the Ba(hfa)2 (tetraglyme) exists at high temperature 1160
http://journals.cambridge.org
J. Mater. Res., Vol. 12, No. 4, Apr 1997
Downloaded: 22 Mar 2015
of 750 ±C. In this study, PEMOCVD was employed to exclude the SrF2 second phase at low deposition temperatures in SrTiO3 deposition using Sr(hfa)2 (tet). SrTiO3 thin films using
Data Loading...
