Integration of microwave termination based on TaN thin films on ferrite substrates

¹ Department of Electrical and Computer Engineering, University of Delaware, Newark, 19716 Delaware, USA
² State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054 Sichuan, P.R. China

^a e-mail: dnzhang163@163.com

Received: 17 December 2014
Revised: 28 May 2015
Accepted: 28 July 2015
Published online: 4 September 2015

Abstract

Integration of microwave discrete devices such as isolators and circulators is highly desired for radar and communication platforms and in particular as components used in transmit and receive (T/R) modules. In those applications, Tantalum nitride (TaN) films are widely used as a surface mounted termination to improve the reliability and performance. In the current work, TaN thin films were directly deposited on polycrystalline ferrite substrate (Ni_0.3Zn_0.7Fe₂O₄) to be integrated with isolators or circulators. The deposition conditions were first optimized to obtain suitable sheet resistance and near zero temperature coefficients of resistance (TCR). Next a 50 Ω microwave termination was designed and fabricated using standard photolithography techniques. Broadband measurements show that the terminator has a low voltage standing wave ratio (VSWR) of less than 1.20 in the frequency range of DC-20 GHz. The measured resistance was between 48 and 54 Ω.