| The 4 GHz bulk acoustic wave (BAW) resontors have been fabricated by thin films of PZT-based ternary perovskite compounds. The piezoelectric Pb(Mn1/3Nb2/3)O3¨CPb(Zr,Ti)O3 (PMnN-PZT) thin films on (100)MgO were deposited by RF magnetron sputtering. The PMnN-PZT thin films shows tetragonal crystal structure and highly (001) orientation. The surface roughness of the thin films was about 2nm. The cross section TEM image of PMnN-PZT shows single domain structure. The bulk acoustic wave (BAW) resonators composed by PMnN-PZT thin films were fabricated by MEMS technology. The RF properties of the resonator were evaluated by VNA (Vector Network Analyzer). The 0.1PMnN-PZT(55/45) thin film¡¡exhibits high electro-mechanical coupling constant kt and high Q-value at 3.87GHz. Values of kt and Q are 0.56 and 185, respectively. These values are highest in our knowledge. In addition, the kt2 Q of 58 is the highest value comparing with those of previously reported PZT-BAW resonators. |