Development of CMOS integrated AlN based SAW-Filter and the role of Si substrate resistivity

Integrated AlN/SiO2/Si(100) delay lines for Rayleigh surface acoustic waves (SAWs) with resonant frequencies up to 3.4 GHz were fabricated using a new CMOS compatible concept. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) images were done to characterize the piezoelectric AlN layer. The roughness of the AlN surface is less than 3 nm. Due to the extremely flat AlN surface, it is possible to produce frequency filters with low losses due to the surface roughness. Furthermore, S-parameter measurements of SAW filters with different substrate resistivities were performed. Large substrate resistivities of 4000 Ωcm lead to a high out-of-band insertion loss due to the reduced capacitive coupling to the Silicon substrate, which is an important parameter for SAW applications. An additional SiO2 layer can further increase the out-of-band insertion loss.

[1]  S. A. Dobershtein,et al.  SAW ring filters with insertion loss of 1 dB , 1994, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[2]  Anthony J. Walton,et al.  Aluminium Nitride thin Film Acoustic Wave Device for Microfluidic and Biosensing Applications , 2010 .

[3]  L. Vergara,et al.  SAW characteristics of AlN films sputtered on silicon substrates. , 2004, Ultrasonics.

[4]  J. Danel,et al.  Trade-Off between Issues in AlN/SiO2/Si Pressure Sensor , 2007, 2007 International Conference on Perspective Technologies and Methods in MEMS Design.

[5]  Kak Namkoong,et al.  Surface acoustic wave immunosensor for real-time detection of hepatitis B surface antibodies in whole blood samples. , 2009, Biosensors & bioelectronics.

[6]  Hong Hu,et al.  Pressure and temperature microsensor based on surface acoustic wave , 2009 .

[7]  Gang Xu,et al.  Pressure and Temperature Microsensor Based on Surface Acoustic Wave in TPMS , 2010 .

[8]  M. Dragoman,et al.  AlN SAW structures for GHz applications , 2008, 2008 Asia-Pacific Microwave Conference.

[9]  M. Shur,et al.  Surface acoustic wave velocity in single-crystal AlN substrates , 2006, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[10]  M. Aguilar,et al.  Influence of sputtering mechanisms on the preferred orientation of aluminum nitride thin films , 2003 .

[11]  Oliver Brandt,et al.  Superhigh-frequency surface-acoustic-wave transducers using AlN layers grown on SiC substrates , 2002 .

[12]  D. Altamura,et al.  Fabrication of AlN/Si SAW delay lines with very low RF signal noise , 2007 .

[13]  M. Vaněček,et al.  ZnO/AlN/diamond layered structure for SAW devices combining high velocity and high electromechanical coupling coefficient , 2005 .

[14]  S. A. Dobershtein,et al.  SAW ring filters with insertion loss of 1 dB , 1997 .

[15]  S. Fujii.  High‐frequency surface acoustic wave filter based on diamond thin film , 2011 .

[16]  M. B. Assouar,et al.  Study of structural and microstructural properties of AlN films deposited on silicon and quartz substrates for surface acoustic wave devices , 2004 .

[17]  P. Kirsch,et al.  5GHz surface acoustic wave devices based on aluminum nitride/diamond layered structure realized using electron beam lithography , 2006 .

[18]  P. Rey,et al.  A novel structure of AlN/SiO2/Si, AlN/Si SAW filter , 2008, 2008 IEEE International Frequency Control Symposium.