Piezoelectric resonator with two narrow support beams and high quality factor

Abstract

The invention belongs to the field of electronic science and technology, relates to an MEMS (Micro-Electro-Mechanical System) piezoelectric resonator and provides a piezoelectric resonator with two narrow support beams and a high quality factor. The piezoelectric resonator comprises a vibration block, an input end support beam, an output end support beam, an input end support table, an output end support table and a base, wherein the vibration block is electrically connected to the support tables through the support beams; the support tables are arranged on the base; external metal electrodes are arranged on the support tables; the vibration block is formed by an input end P type semiconductor area and an N type semiconductor area, wherein the input end P type semiconductor area is arranged at a connection place of the vibration block and the input end support beam; the support beams for connecting the areas of the vibration blocks and the corresponding areas of the vibration block adopt the same doping type; a piezoelectric layer partially covers the vibration block; a notch is partially exposed out of the input end P type semiconductor area; and a metal electrode arranged on the piezoelectric layer is connected to the input end P type semiconductor area through a transition metal electrode. According to the structure, the width of the support beams can be greatly reduced and the quality factor Q of the resonator can be effectively improved.

Description

technical field [0001] The invention belongs to the field of electronic science and technology, and relates to a radio frequency micro-electromechanical system (RF MEMS) device, especially a MEMS piezoelectric resonator. Background technique [0002] Resonators are one of the key devices in electronic equipment. At present, quartz crystal resonators are mainly used in electronic equipment. However, with the further requirements for high performance and miniaturization of electronic equipment, the large volume and high power of quartz crystal resonators Disadvantages such as power consumption and incompatibility with IC processes have become very prominent. MEMS piezoelectric resonator is a high-performance resonator device based on micro-mechanical technology and micro-mechanical vibration. It has the advantages of small size, low power consumption, and compatibility with IC technology, making it a good choice for the development of system miniaturization. Prospects. [00...

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Problems solved by technology

[0003] At present, the MEMS resonators that have been studied more are mainly micromechanical piezoelectric resonators. This type of resonator converts the input electrical signal into a mechanical signal through the energy conversion structure, and then converts the mechanical signal into an electrical signal output through the energy conversion structure; The piezoelectric layer of this type of resonator is integrated with the vibrating block. Because of the need for input, output and grounding channels, it is usually used to grow a layer of silicon dioxide insulating layer on the support beam, and then etch the metal connection on the insulating layer. The traces are connected to the external support platform; due to the alignment error of each material layer during etching, the lower layer material needs to be designed with edge redundancy to prevent the upper layer material from collapsing due to misalignment, so this design will cause The width of the single crystal silicon at the bottom of the support beam is much larger than the minimum line width of the top metal layer. When the resonator vibrates mechanically, more energy is dissipated at the anchor point through the support beam, making the anchor point of the resonator The increase in loss severely limits the improvement of the quality factor Q of the resonator, which will inevitably affect the further improvement of the performance of the resonator

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