Combinatorial synthesis of (Al,Ti)N thin films via pulsed laser deposition
- PDF / 149,875 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 26 Downloads / 230 Views
0894-LL02-07.1
Combinatorial synthesis of (Al,Ti)N thin films via pulsed laser deposition Clara Ji-Hyun Cho1, V. Siva Kumar G. Kelekanjeri1, Rosario A. Gerhardt1 and Hideomi Koinuma2 1 School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0245. 2
Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama 226-8503, Japan. Presently at National Institute of Materials Science, Japan. ABSTRACT
Aluminum nitride (AlN), a wide band gap semiconductor (Eg = 6.2eV), has potential applications in microelectronics due to its excellent insulating properties and compatibility with silicon [1,2]. More recently, the use of AlN thin films in high electron mobility transistors, light emitting diodes and UV sources is explored by altering the band gap of the material [3]. The present work describes the combinatorial synthesis of (Al,Ti)N thin films via pulsed laser deposition (PLD) technique to obtain desirable compositional spreads and corresponding variations in the electrical properties. Films of AlN, TiN and (Al,Ti)N were deposited on 6H-SiC (0001) substrates held at a temperature of 680°C. The surface quality of the films examined using an AFM revealed island growth of SiO2 and other growth patterns possibly related to substrate defects. X-ray diffraction studies indicated that the growth of AlN and TiN films occurred with corresponding habit planes of (0002) and (111) parallel to the substrate surface. Compositional investigations conducted using energy dispersive spectroscopy (EDS) and x-ray photoelectron spectroscopy (XPS) showed systematic changes in the Al and Ti composition across the thickness of the compositional spread film. Cross-sectional analysis of (Al,Ti)N films conducted in a high-resolution transmission electron microscope revealed that the films were multi-layered. Several orders of magnitude decrease in the measured resistivity across a 15 mm length (Al,Ti)N film was noted corresponding to a systematic increase in the Ti content. Further optimization of deposition conditions is essential for producing thicker films. INTRODUCTION The potential for using group III nitrides in applications such as optoelectronics and high power electronics has been realized and implemented by various researchers over the past few years. The key feature of these materials that lend themselves for device applications is their large direct energy bandgap, through the use of bandgap engineering. Other interesting properties of group III nitrides include high melting points, high thermal conductivities, low dielectric constants, high breakdown voltage, good mechanical properties and the ability to resist radiation damage. Aluminum nitride (AlN) is an insulator with a wide direct energy bandgap (Eg) of 6.2 eV. The large difference in electronegativity between Al (1.18) and N (3.0) leads to a very strong
0894-LL02-07.2
chemical bond with a wide direct energy bandgap. AlN among all group III nitrides is a particularly interesting material because of the diverse range of appl
Data Loading...
