High-Performance Single-Side Fabricated (111)-Silicon Dual-Cantilever Accelerometer with Squeeze-Film Air Damping Modulation

Abstract

This study proposes a novel design and micromachining process for a dual-cantilever accelerometer. Comb and curved-surface structures are integrated into the sensing structure to modulate the squeeze-film damping, thus effectively optimizing the response frequency bandwidth. Owing to the high stress concentration on the dual-cantilever integrated with a fully sensitive piezoresistive Wheatstone bridge, a high sensitivity to acceleration is achieved. In addition, the dual-cantilever accelerometer is fabricated using a specifically developed low-cost and high-yield (111)-silicon single-side bulk-micromachining process. The test results show that the proposed dual-cantilever accelerometer exhibits a sensitivity of 0.086–0.088 mV/g/3.3 V and a nonlinearity of ±(0.09%–0.23%) FS (full-scale). Based on dynamic characterization, an adequate frequency bandwidth of 2.64 kHz is verified. Furthermore, a resonant frequency of 4.388 kHz is measured, and a low quality factor (Q) of 7.62 is obtained, which agrees well with the design for air-damping modulation. The achieved high performance renders the proposed dual-cantilever accelerometer promising in applications such as automotive and consumer electronics.

摘要

本研究提出了一种新型双悬臂加速度计的设计和微加工工艺技术。传感结构中集成有梳齿和空气微间隙结构，以调节压膜空气阻尼效应，进而有效地优化了传感器的频率响应和带宽特性。由于压阻惠斯通全桥集成在双悬臂梁上实现了高效率的应力集中，实现了对加速度检测的高灵敏度。此外，双悬臂加速度计采用了具有低成本和高成品率的(111)硅单面体微加工工艺来实现制造。传感器测试结果表明，所提出的双悬臂加速度计的灵敏度为0.086~0.088 mV/g/3.3V，全量程的非线性为±(0.09%~0.23%)。动态特性表征结果显示了2.64 kHz的充足频率带宽。传感器具有4.388 kHz谐振频率，并将品质因子（Q值）控制在7.62，与空气阻尼调制效应的设计结果高度一致。该双悬臂加速度计实现了较高的性能，在汽车和消费电子等领域具有很好的应用前景。