Patent ID: 11909373
Assignee: GLOBAL COMMUNICATION SEMICONDUCTORS, LLC
Field: Basic communication processes (Electrical engineering)
Classification: CPC H | IPC H

Claim 9:
10. A bulk acoustic resonator, comprising:
a substrate; and
a stack over the substrate, the stack including a first electrode, a second electrode, and a piezoelectric layer between the first electrode and the second electrode; wherein:
a region of overlap of the first electrode, the second electrode and the piezoelectric layer forms an active region of the stack;
the piezoelectric layer has a trench extending parallel to a boundary of the active region, the trench has an outer sidewall facing the active region surrounded by the trench, an inner sidewall facing the outer sidewall, and a bottom surface;
the second electrode extends from a top surface of the piezoelectric layer in the active region to cover the inner sidewall, the bottom surface, and the outer sidewall of the trench; and
the trench provides an air gap between a portion of the second electrode on the inner sidewall and a portion of the second electrode on the outer sidewall.