AIR GAP IN BAW TOP METAL STACK FOR REDUCED RESISTIVE AND ACOUSTIC LOSS

摘要

Embodiments of a Bulk Acoustic Wave (BAW) device including a high conductivity electrode are disclosed. In some embodiments, a BAW device includes a piezoelectric layer, a first electrode on a first surface of the piezoelectric layer, and a second electrode on a second surface of the piezoelectric layer opposite the first electrode. The second electrode includes a first metal layer and a second metal layer. The second metal layer is on the second surface of the piezoelectric layer, and the first metal layer is over a surface of the second metal layer opposite the piezoelectric layer, where the first metal layer is separated from the second metal layer by an air gap. By including the air gap, the thickness of the first metal layer (e.g., a high conductivity layer) can be increased to thereby increase the electrical conductivity of the second electrode while maintaining the performance of the BAW device.

主权项

1. A Bulk Acoustic Wave (BAW) device, comprising:
a piezoelectric layer; a first electrode on a first surface of the piezoelectric layer; and a second electrode on a second surface of the piezoelectric layer opposite the first electrode, the second electrode comprising a first metal layer and a second metal layer, wherein
the second metal layer is on the second surface of the piezoelectric layer; andthe first metal layer is over a surface of the second metal layer opposite the piezoelectric layer, the first metal layer being separated from the second metal layer by an air gap.