Power Handling Improvement in Cross-Sectional Lame Mode Resonators Operating in the Ku-band

TL;DR

This paper demonstrates enhanced power handling in Ku-band cross-sectional Lame-Mode Resonators by using thermally stable AlSiCu electrodes, achieving up to 6 dBm higher input power capacity and improved device performance.

Contribution

It introduces a thermal model-guided material selection for electrodes, significantly improving power handling and reliability of CLMRs in the Ku-band.

Findings

AlSiCu electrodes prevent electromigration and performance degradation.

Maximum input power increased by up to 6 dBm with AlSiCu.

Resonators achieved Qm of 360 and QBode of 500.

Abstract

This study presents power handling improvements in cross-sectional Lame-Mode Resonators (CLMRs) designed for operation in the Ku-band. Previously fabricated CLMR devices failed at approximately 8 dBm of input power, primarily due to electromigration in the aluminum interdigitated electrodes (IDTs). To better understand this mechanism in CLMRs, a data driven thermal model is developed to analyze localized heating effects within the resonator body, which are known to accelerate electromigration. Based on insights from this model, Aluminum Silicon Copper (AlSiCu) was selected for the IDTs due to its superior thermal stability and resistance to electromigration. Devices fabricated with AlSiCu exhibited no signs of performance degradation, with the best-performing resonator achieving a mechanical quality factor (Qm) of 360, a maximum Bode quality factor (QBode) of 500, and an electromechanical coupling coefficient (kt2) of 6.3%. Moreover, the use of AlSiCu significantly increased the maximum input power the device can withstand, showing an improvement of up to 6 dBm over previous devices. These improvements in power handling make the devices strong candidates for high-power Ku-band filtering applications.