Patent ID: 11949397
Assignee: ROFS MICROSYSTEM (TIANJIN) CO., LTD
Field: Basic communication processes (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A bulk acoustic wave resonator, the bulk acoustic wave resonator comprising:
a substrate,
a lower electrode arranged on the substrate,
a piezoelectric layer arranged on the lower electrode,
an upper electrode arranged on the piezoelectric layer and an acoustic mirror arranged between the substrate and the lower electrode, and
an air gap with an arch-shaped upper surface arranged at the external of the effective piezoelectric region, the air gap being formed between the upper electrode and the piezoelectric layer and/or between the piezoelectric layer and the substrate, and covering the end part, proximal to the air gap, of the lower electrode or connecting to the end part of the lower electrode;
wherein mutual overlapping regions of the upper electrode, the piezoelectric layer and the lower electrode in a thickness direction form an effective piezoelectric region, and the effective piezoelectric region in the thickness direction is located in a region, in which the acoustic mirror is located; and
wherein the air gap is provided with a first end proximal to the effective piezoelectric region, the arch-shaped upper surface is at least a portion of the upper surface of the air gap, the arch-sped upper surface of the air gap is starting from the first end proximal to the effective piezoelectric region.