Properties of high resistivity CoPdAlO film for possibility of application to RF integrated inductor

Abstract

Presently, an inductor adapted at MMIC (Monolithic microwave integrated circuit) which is used for cellular phone or PHS operates at quasimicrowave range over 800 MHz. However, a W-CDMA (Wideband code division multiple access) will use about 2 GHz range. Therefore magnetic film devices should be compatible up to 2 GHz. We deposited Co-Pd-Al-O system film using rf sputtering method which is expected for operating at 2 GHz, and investigated the effect of Pd content and magnetic field annealing. When Pd composition is 19%, H/sub k/ was 118 Oe, and showed flat frequency characteristics until 1.5 GHz. The Q factor (=/spl mu/'//spl mu/") was 23.3 at 1 GHz, 6.7 at 1.5 GHz and 1.5 at 2 GHz, respectively. Resonance frequency was 2.9 GHz, therefore Co-Pd-Al-O thin film could be used at over 1 GHz, and also expected as an inductor material for next generation MMIC.