Accession Number:

ADA433525

Title:

High Performance Nano-Constituent Buffer Layer Thin Films to Enable Low Cost Integrated On-the-Move Communications Systems

Descriptive Note:

Conference paper

Corporate Author:

ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE

Report Date:

2004-12-01

Pagination or Media Count:

9.0

Abstract:

Successful integration of paraelectric Ba1-xSrxTiO3 BST based thin films with affordable Si substrates has a potential significant commercial impact as the demand for high-frequency tunable devices intensifies. Utilizing a coplanar device design we successfully designed, fabricated, characterized, and optimized a high performance Ta2O5 thin film passive buffer layer on Si substrates, which will allow the integration of BST films with large area affordable Si substrates. This passive buffer layer thin film was fabricated via the industry standard metalorganic solution decomposition technique. The anneal optimized Ta2O5 based thin film possessed excellent material properties. Specifically, these material properties include an enhanced dielectric constant epsilon r 45.6, low dielectric loss tan delta0.006, low leakage current or high film resistivity rho10 to the 12th Omega-cm at E1 MVcm, excellent temperature stability temperature coefficient of capacitance of 52 ppmdeg C, and excellent bias stability of capacitance 1.41 at 1 MVcm. Additionally, the permittivity and dissipation factor exhibited minimal dielectric dispersion with frequency. The dielectric passive buffer layer film was typified by a uniform dense microstructure with minimal defects, and a smooth, nano-scale fine grain, crackpinhole free surface morphology. This work also demonstrated that the coefficient of thermal expansionCTE mismatch between the Ta2O5 buffer and BST active thin films in the coplanar device design serves to enhance the dielectric tunability of the device. The development of this passive buffer layer thin film materials technology will enable the direct integration of paraelectric active thin films BST with silicon substrates. The impact of this materials technology is paramount, as this phase shifter materials technology design will promote broad scale implementation of affordable On The Move OTM phased array antenna systems across a variety of platform7

Subject Categories:

  • Electrical and Electronic Equipment

Distribution Statement:

APPROVED FOR PUBLIC RELEASE