This work presents a new acoustic MEMS resonator technology, dubbed Aluminum Nitride (AlN) Combined Overtone Resonator (COR), capable of addressing the filter requirements for the 5G high frequency bands in the 6-40GHz range. The COR exploits the multimodal excitation of two higher-order Lamb waves ( $2^{\mathbf {nd}}$ and $3^{\mathbf {rd}}$ order Asymmetrical Lamb Waves) in a suspended thin-film AlN plate to transduce a 2-dimensional vibration mode with high electromechanical coupling coefficient $k_{t}^{2}$ (up to 1.9%) and quality factor $Q>1100 $ at twice the frequency of a fundamental thickness-extensional mode in the same structure. Analytical and finite-element method (FEM) models are developed to describe the working principle of the COR technology and predict the achievable $k_{t}^{2}$ , Q and lithographic frequency tunability. An 8.8 GHz COR prototype was fabricated showing a high $k_{t}^{2}~\sim ~0.3$ % (using a simple top-electrode-only configuration with a 2-mask process) and a groundbreaking $Q\sim {1100}$ which is the highest ever achieved among piezoelectric resonators above 6 GHz. The $f - Q$ product $\sim 1\times 10 ^{\mathbf {13}}$ is the highest among all demonstrated piezoelectric resonators with metallic coverage >50%. Additionally, the capability of the COR technology to deliver contiguous filters with bandwidths between 355 and 592 MHz (aggregated BW >2GHz) in the mmWave spectrum, with relaxed lithographic requirements, is demonstrated by FEM. [2019-0229]

中文翻译：

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用于 5G 高频段的氮化铝组合泛音谐振器

这项工作提出了一种新的声学 MEMS 谐振器技术，称为氮化铝 (AlN) 组合泛音谐振器 (COR)，能够满足 6-40GHz 范围内 5G 高频段的滤波器要求。COR 利用两个高阶兰姆波的多模态激发（ $2^{\mathbf {nd}}$ 和 $3^{\mathbf {rd}}$ 订购非对称兰姆波）在悬浮薄膜 AlN 板中转换具有高机电耦合系数的二维振动模式 $k_{t}^{2}$ （高达 1.9%）和品质因数 $Q>1100 $ 相同结构中基本厚度扩展模式的频率的两倍。开发了分析和有限元方法 (FEM) 模型来描述 COR 技术的工作原理并预测可实现的 $k_{t}^{2}$ , Q 和光刻频率可调性。制造了一个 8.8 GHz COR 原型，显示出高 $k_{t}^{2}~\sim ~0.3$ %（使用简单的顶部电极配置和 2 掩模工艺）和突破性的 $Q\sim {1100}$ 这是 6 GHz 以上压电谐振器中最高的。这 $f - Q$ 产品 $\sim 1\times 10 ^{\mathbf {13}}$ 在所有展示的压电谐振器中是最高的，金属覆盖率 >50%。此外，FEM 证明了 COR 技术能够在毫米波频谱中提供带宽在 355 到 592 MHz（聚合带宽 > 2GHz）之间的连续滤波器，同时满足宽松的光刻要求。[2019-0229]