Avramov I D
Inst. of Solid State Phys., Sofia.
IEEE Trans Ultrason Ferroelectr Freq Control. 1990;37(6):530-4. doi: 10.1109/58.63109.
An experimental study of metal strip surface skimming bulk wave (SSBW) resonators using a surface acoustic wave (SAW) design is presented. Characteristics of SSBW and SAW resonators fabricated with the same photolithographic mask are compared and discussed. High Q low-loss SSBW resonators are achieved using a conventional two-port SAW resonator design and taking special care of the distance L between both interdigital transducers, the metal thickness h/lambda (lambda=acoustic wavelength) and the finger-to-gap ratio. Best overall performance of the SSBW devices in this study is achieved at L=nlambda/2-lambda/4 (compared with L=nlambda/2-lambda/8 for SAW resonators), h /lambda=1.6% (compared with 2% for SAW), and finger-to-gap ratio close to 1. The best device fabricated shows an unloaded Q of 5820 and an insertion loss of 7.8 dB at 766 MHz. The SSBW resonant frequency shows a stronger dependence on the metal thickness than the SAW one. This problem, however, is readily solved by frequency trimming using a CF(4) plasma etching technique. SSBW resonator can be trimmed by 0.2% down in frequency (compared with 0.05% for SAW) without affecting their performance.
本文介绍了一项使用表面声波（SAW）设计的金属条表面掠射体波（SSBW）谐振器的实验研究。比较并讨论了用相同光刻掩模制造的SSBW谐振器和SAW谐振器的特性。采用传统的两端口SAW谐振器设计，并特别注意两个叉指换能器之间的距离L、金属厚度h/λ（λ=声波波长）和指间距比，从而实现了高Q低损耗的SSBW谐振器。本研究中，SSBW器件的最佳整体性能在L=nλ/2-λ/4时实现（相比之下，SAW谐振器为L=nλ/2-λ/8），h/λ=1.6%（相比之下，SAW为2%），且指间距比接近1。所制造的最佳器件在766 MHz时的空载Q为5820，插入损耗为7.8 dB。SSBW谐振频率对金属厚度的依赖性比SAW更强。然而，通过使用CF(4)等离子体蚀刻技术进行频率微调，这个问题很容易解决。SSBW谐振器的频率可以下调0.2%（相比之下，SAW为0.05%）而不影响其性能。
