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近几年来,声表面波谐振器已经发展到在甚高频和超高频振荡器电路中使用的程度。与使用倍频电路的低频体波晶体相反,使振荡器工作在末级频率上的优点是众所周知的。如果要求用商用频率源复盖整个频带,就需要许多掩模,(因为一个掩模生产一个单一频率的谐振器)或一个有效的调节程序。为了减少所要求的掩模数,这个调节程序必须调节范围宽,对器件的其他特性影响小。对石英的反应式或离子刻蚀满足了这些原则。据文献报道,这种技术可以用来以隐埋的或者表面的换能器和以开槽反射器调节谐振器。我们的这些器件,是用镀铝表面换能器和反射器制成的。用CF_4和O_2等离子在平面反应器上刻蚀,结果在石英中刻蚀出了沟槽,并且对起掩模作用的铝模的影响极小。这些沟槽导致换能器和反射器组合中表面波速度较低,从而使频率向下偏移。以这样的速度同时产生的偏移可以用来在器件性能下降过大之前提供很大的调节范围。这样刻蚀可以影响器件的电特性和转折点温度。本文就甚高频频段的谐振器,研究这两种特性对器件的影响。还介绍了工作在194MHz上的谐振器的数据。
In recent years, surface acoustic wave resonators have been developed to the degree used in VHF and UHF oscillator circuits. The advantage of operating an oscillator on the final frequency, as opposed to a low frequency body wave crystal using a frequency multiplier circuit, is well known. If it is required to cover the entire frequency band with a commercial frequency source, many masks are needed (because one mask produces a single frequency resonator) or an effective conditioning procedure. In order to reduce the required number of masks, this adjustment procedure must have a wide adjustment range and have little effect on the other characteristics of the device. These principles are satisfied by the reactive or ion etching of quartz. It has been reported in the literature that this technique can be used to tune resonators with buried or surface transducers and slotted reflectors. These of our devices are made of aluminized surface transducers and reflectors. Etching with CF 4 and O 2 plasma on a planar reactor resulted in the trenches being etched into the quartz and the effect on the masking aluminum mold was minimal. These trenches result in lower surface wave velocities in the transducer and reflector combination, shifting the frequency downwards. Offsets generated at the same time at this rate can be used to provide a large adjustment range before the device performance drops too much. Such etching can affect the electrical characteristics of the device and the turning point temperature. In this paper, the very high frequency band resonator, the impact of these two characteristics on the device. The data of resonators working at 194MHz is also introduced.