Bulk acoustic wave resonator and manufacturing method thereof

Abstract

The invention discloses a bulk acoustic wave resonator and a manufacturing method thereof. The resonator comprises a substrate on which a sound wave reflection structure is formed, and a bottom electrode layer, a piezoelectric layer and a top electrode layer which are sequentially formed above the sound wave reflection structure, from the angle of projection of the piezoelectric layer to the substrate, at least part of the piezoelectric layer is provided with a fracture area, the fracture area is provided with a first edge and a second edge which are opposite, the first edge does not exceed the edge of the top electrode layer, and the second edge extends out of the edge of the bottom electrode layer. And bombardment ions different from materials forming the piezoelectric layer are contained in the fracture region. According to the invention, ion bombardment is carried out at a certain depth on the piezoelectric layer of the area, extending out of the edge of the bottom electrode, in the sound wave reflection structure, so that molecular bonds of piezoelectric crystals in the area are broken, the conduction effect is reduced or eliminated, and parasitic oscillation generated by the resonator in the area can be greatly reduced.

Description

technical field [0001] The present application relates to the field of semiconductor devices, and mainly relates to a bulk acoustic wave resonator and a manufacturing method thereof. Background technique [0002] The simple structure of a thin-film bulk acoustic resonator consists of two opposing plate electrodes with a piezoelectric crystal material sandwiched between them. Under working conditions, a voltage is applied to the electrodes, and the piezoelectric crystal material uses the inverse piezoelectric effect to convert the electrical signal into a mechanical resonance, and then uses the piezoelectric effect to convert the mechanical resonance into an electrical signal output. The atomic arrangement of the piezoelectric crystal is asymmetrical. Although the atomic arrangement of the piezoelectric crystal is asymmetrical, the positive charges and the nearby negative charges cancel each other out, so the overall crystal is not charged. When the crystal is subjected to p...

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Problems solved by technology

[0003] In the prior art, the thin film bulk acoustic resonator is connected to the outside world through the top electrode directly leading out, but such a connection will result in the overlapping area of ​​the top electrode and the bottom electrode, and the overlapping area is in the area corresponding to the non-cavity , so additional piezoelectric oscillations are generated, and spurious spurious signals appear, which in turn leads to deterioration of the resonator performance

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