The effects of ionizing radiation on SAW resonators

SAW resonators with frequencies ranging from 199 MHz to 746 MHz were fabricated and exposed to sequentially increasing total doses of various types of ionizing radiation, and the effects were observed. The substrates used were air-swept and as-grown (nonswept) 40° Y-rotated quartz, LST-quartz, and nonswept 40° Y-rotated quartz coated with a 400-Å-thick layer of SiO_x. The total doses used range from 1 kRad(Si) to 10 MRad(Si), and the radiation types tested were Co-60 gamma, high energy electron (β), proton, and heavy ion (Si-28, Cl-35, Ge-74, and Au-197) radiation. The measurement results show a distinct difference in the radiation sensitivity of SAW device performance parameters based on the substrate used. The effects of the passivating SiO_x layer were also interesting, since the coated devices exhibited significantly smaller radiation-induced changes than those without the coating