Micromachined Heterostructured Lamb Mode Waveguides for Acoustoelectric Signal Processing
Micromachined Heterostructured Lamb Mode Waveguides for Acoustoelectric Signal Processing
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DOI：
10.1109/tmtt.2022.3194723
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发表时间：
2022-11
影响因子：
4.3
通讯作者：
Hakhamanesh Mansoorzare;R. Abdolvand
中科院分区：
文献类型：
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作者：
Hakhamanesh Mansoorzare;R. Abdolvand
这项工作探索了利用声学声子和电子之间的强烈相互作用来实现射频(RF)信号放大或衰减的微机械异质结构波导。一种薄膜压电-半导体叠层被定制成产生高机电耦合的兰姆波，该兰姆波受到微声波导中高迁移率电子的影响。兰姆波是由射频信号通过压电层上的交指电极产生的；通过向半导体层施加电压，使电子引导机械波，射频信号通过声电(AE)效应被放大。相反，传播速度更快或与电子流方向相反的信号会受到衰减，从而导致波导的非互易性。声发射效应的研究始于20世纪中叶，到目前为止主要集中在声表面波(SAW)。在高质量的Nb酸锂(LN)和硅(Si)键合薄膜的支持下，研究表明，在100MHZ的S频率下，基对称兰姆模波导可以在偏置功耗小于10 mW的情况下获得超过40dB的声发射增益和强的非互易传输。这可以实现对干扰消除和全双工无线电至关重要的开关、延迟线、隔离器和环行器。在一些更高的$S0$谐波中，声发射效应被观察到更强，允许使用具有更宽松的临界尺寸的优化电极来缩放到更高的频率。此外，在这项工作中测量到的高达5.5分贝的持续终端增益意味着无晶体管放大器的潜力，可以与更传统的声学设备以单芯片的方式协同实施。
This work explores micromachined heterostructured waveguides that leverage strong interactions between acoustic phonons and electrons to enable radio frequency (RF) signal amplification or attenuation. A thin-film piezoelectric-on-semiconductor stack is tailored to generate high electromechanical coupling Lamb waves that are impacted by high mobility electrons within a microacoustic waveguide. Lamb waves are generated by RF signal via interdigital electrodes on the piezoelectric layer; by applying a voltage to the semiconductor layer so that the electrons lead mechanical waves, the RF signal is amplified through the acoustoelectric (AE) effect. Conversely, the signals propagating faster or in the opposite direction of the electron flow undergo attenuation, rendering the waveguide nonreciprocal. Research on the AE effect dates to the mid-20th century and until now has been mostly focused on surface acoustic waves (SAWs). In this work, enabled by high-quality bonded thin films of lithium niobate (LN) and silicon (Si), it is shown that fundamental symmetric ( $S0$ ) Lamb mode waveguides at 100 s of MHz can achieve more than 40 dB of AE gain and strong nonreciprocal transmission with less than 10 mW of bias power consumption. This could enable implementation of switches, delay lines, isolators, and circulators, which are critical for interference cancellation and full-duplex radio. The AE effect is observed to be stronger in some higher $S0$ harmonics, allowing for scaling to higher frequencies with optimized electrodes that have more relaxed critical dimensions. In addition, up to 5.5-dB sustained terminal gain measured in this work implies the potential for transistor-less amplifiers that could be implemented in concert with more traditional acoustic devices in a single-chip manner.