**12. References**

Akiyama M., Xu C.-N., Nonaka K., Shobu K., Watanabe T., *Thin Solid Films*, 315 (1998) 62


Buck V., Deuerler F., *Diamond Relat. Mater*. 7 (1998) 1544

Buck V*., J. Opto. Adv. Mater*. 10 (2008) 85

Caliendo C., *Appl. Phys. Lett*. 83 (2003) 4851

Campbell C., Academic Press (1989)

Chalker P. R., Joyce T. B., Johnston C., Crossley J. A. A., Huddlestone J., Whitfield M. D., Jackman R. B., *Diamond Relat. Mater*. 8 (1999) 309

Dubois M.-A., Muralt P., *J. Appl. Phys*., 89 (2001) 6389

Erdemir A., Fenske G. R., Krauss A. R., Gruen D. M., McCauley T., Csencsits R. T., *Surf. Coat. Techn*., 120-121 (1999) 565- 572


This feasibility study indicates that the SAW velocity and coupling coefficient only depend on the relative thickness of ALN and UNCD films, but are not affected by IDT pattern.

Fig. 11. Schematic Pattern design of SAW Resonator. The actual device consists of significant

The authors like to thank Dr. Dieter Schneider at Fraunhofer IWS Dresden for the Emodulus measurements of the UNCD films and Hanna Bukowska, University Duisburg-

Akiyama M., Xu C.-N., Nonaka K., Shobu K., Watanabe T., *Thin Solid Films*, 315 (1998) 62 Assouar M. B., El Hakiki M., Elmazria O., Alnot P., Tiusan C., *Diamond Relat. Mater*. 13

Auciello O., Birrell J.,. Carlisle J. A, Gerbi J. E., Xiao X., Peng B., Espinosa H. D., *J. Phys.:* 

Bi B., Huang W. -S., Asmussen J., Golding B., *Diamond Relat. Mater*. Vol. 11, Issues 3-6 (2002)

Chalker P. R., Joyce T. B., Johnston C., Crossley J. A. A., Huddlestone J., Whitfield M. D.,

Erdemir A., Fenske G. R., Krauss A. R., Gruen D. M., McCauley T., Csencsits R. T., *Surf.* 

more lines

**11. Acknowledgment** 

**12. References** 

Essen for the AFM measurements.

(2004) 1111

677-680

*Condens. Matter* 16 (2004) R539

Buck V*., J. Opto. Adv. Mater*. 10 (2008) 85 Caliendo C., *Appl. Phys. Lett*. 83 (2003) 4851 Campbell C., Academic Press (1989)

Buck V., Deuerler F., *Diamond Relat. Mater*. 7 (1998) 1544

Dubois M.-A., Muralt P., *J. Appl. Phys*., 89 (2001) 6389

*Coat. Techn*., 120-121 (1999) 565- 572

Jackman R. B., *Diamond Relat. Mater*. 8 (1999) 309


**Aluminum Nitride (AlN)** 

Jyoti Prakash Kar1 and Gouranga Bose2

*1Italy 2India* 

**Film Based Acoustic Devices:** 

**Material Synthesis and Device Fabrication** 

Enormous growth has taken place in electronics, especially in the field of RF communications towards the beginning of 21st century and continuously striving for better communication performance. Presently, the key concerns of RF communications is bandwidth, in the range of low/medium GHz range, to avoid frequency crowding, especially for wireless communication mobile handsets and base stations (Kim et al., 2004). In addition, reduction in signal loss, low power consumption, scaling down device size, reduction in materials and fabrication costs, and packaging of the device are main issues today. Some of these issues can be resolved, if the new generation of electroacoustic devices can be monolithically integrated with integrated circuit (IC). Conventional electroacoustic devices, used in the communication e.g. Surface Acoustic Wave (SAW) and Bulk Acoustic Wave (BAW) based systems, are widely used for today's wireless communication. These devices are typically made on a single crystal piezoelectric substrate such as quartz, lithium niobate, and lithium tantalate (Assouar et al., 2004). Unfortunately, these substrates based electroacoustic devices are made separately and then it is wired with the signal processing chip, which has several limitations, in particular low acoustic wave velocity and high frequency device fabrication. To resolve these two core issues, thin film materials based electroacoustic devices are actively under consideration [Bender et al., 2003]. Where, a crystalline film is grown on a particular substrate, especially silicon wafer and electroacoustic device is made out of crystalline film. Thus, the electroacoustic device can be integrated with the signal processing circuit. Apart from the silicon wafer as a base material for crystalline film deposition, a variety of other substrates are also explored for academic and technology interests. Furthermore, to get electroacoustic devices of better quality in terms of high frequency and high quality factor (Q), the piezoelectric property of the film is also exploited with different type of device concept called "Micro-Electro-Mechanical Systems" (MEMS). Thin film bulk acoustic resonators (TFBAR) comes under this MEMS devices, where the crystalline film is made to resonate at RF frequency. These MEMS

**1. Introduction** 

*1Department of Electronics Engineering, University of Tor Vergata, Rome 2Department of Applied Electronics and Instrumentation Engineering, Institute of Technical Education and Research, Bhubaneswar, Orissa* 

Yang W. et al., *Nature Materials* 1, (2002) 253257 Yugo S., Kanai T., Kimura T., Muto T., *Appl. Phys. Lett*. 58, (1991) 1036 **25** 

*2India* 
