Patent ID: 9748918
Date: 2017-08-29
CPC Classifications: H03H

Claim:
1. An acoustic resonator structure comprising: a first electrode disposed on a substrate; a piezoelectric layer disposed on the first electrode; a second electrode disposed on the piezoelectric layer; a frame disposed within a main membrane region defined by an overlap between the first electrode, the piezoelectric layer, and the second electrode, and having an outer edge substantially aligned with a boundary of the main membrane region; a collar formed separate from the frame, disposed outside the main membrane region, and having an inner edge substantially aligned with the boundary of or overlapping the main membrane region; a temperature compensation feature having a positive temperature coefficient for offsetting at least a portion of a negative temperature coefficient of the piezoelectric layer, the first electrode, and the second electrode; and a planarization layer disposed on the piezoelectric layer adjacent to the second electrode, wherein the collar is disposed on the planarization layer and the second electrode.