Search

CN-121974288-A - MEMS piezoelectric device

CN121974288ACN 121974288 ACN121974288 ACN 121974288ACN-121974288-A

Abstract

The application provides a MEMS piezoelectric device, which relates to the technical field of semiconductors and comprises a substrate with a cavity, wherein at least one layer of first electrode layer is laminated on the substrate in the area of the cavity, at least one layer of second electrode layer is laminated on the substrate in the area outside the cavity, the second electrode layer is at least positioned on one side of the cavity, the second electrode layer and the first electrode layer which are on the same layer are arranged at intervals, and piezoelectric layers are formed on the second electrode layer and the first electrode layer. The problem of precipitation of the grain boundary of the high-doped piezoelectric layer can be solved, the piezoelectric layer grown in the non-effective area has enough smoothness, other structural layers which are continuously deposited above the piezoelectric layer in the non-effective area, and metal wires, pads and the like which are laid above the piezoelectric layer have good smoothness, so that the MEMS manufacturing precision is higher.

Inventors

  • ZHANG SONGSONG
  • WANG LEI

Assignees

  • 成都纤声科技有限公司

Dates

Publication Date
20260505
Application Date
20260209

Claims (6)

  1. 1. A MEMS piezoelectric device is characterized by comprising a substrate with a cavity, wherein at least one first electrode layer is laminated on the substrate in the area of the cavity, at least one second electrode layer is laminated on the substrate in the area outside the cavity, the second electrode layer is at least positioned on one side of the cavity, the second electrode layer and the first electrode layer which are arranged at intervals are arranged on the same layer, and piezoelectric layers are formed on the second electrode layer and the first electrode layer.
  2. 2. The MEMS piezoelectric device of claim 1, wherein the substrate comprises a silicon substrate, the silicon substrate being located outside the cavity, the second electrode layer being disposed on the silicon substrate.
  3. 3. The MEMS piezoelectric device according to claim 1, wherein the first electrode layer comprises greater than 80% of an area corresponding to the piezoelectric layer and the second electrode layer comprises greater than 80% of an area corresponding to the piezoelectric layer.
  4. 4. The MEMS piezoelectric device of claim 1, wherein the thickness of the first electrode layer and the second electrode layer is not greater than 1/3 of the thickness of the piezoelectric layer in the stacking direction.
  5. 5. The MEMS piezoelectric device of any one of claims 1-4, wherein the first electrode layer and the second electrode layer are separated by a slit, and a minimum width of the slit is a minimum width of a reticle corresponding to the electrode layer.
  6. 6. A MEMS piezoelectric device according to any one of claims 1 to 4, wherein the piezoelectric layer is further provided with a functional structural layer.

Description

MEMS piezoelectric device Technical Field The application relates to the technical field of semiconductors, in particular to an MEMS piezoelectric device. Background A piezoelectric MEMS (microelectromechanical system, microElectroMechanical systems) sensor is a micro-sensor that uses piezoelectric material for etching processing, and uses a vibrating membrane of a MEMS chip microstructure as a core structural element. Generally, the etching process flow, namely stacking the design components layer by layer, generally, the higher the etching precision is, the higher the deposition quality of the components required by each layer is, and the better the MEMS sensor chip finally shows the ground effect. It is obvious that various sensors manufactured by utilizing the MEMS structure at present have the advantages of small size, high convenience, functional use, reduction of finished products after large-scale mass production and the like, and the MEMS sensor gradually becomes a main stream sensing device in the market. In particular, the present research on piezoelectric materials shows that, for example, aluminum nitride piezoelectric ceramic materials, the addition of some highly doped elements, such as scandium, can generally improve the performance of MEMS piezoelectric films, and thus new materials, particularly highly doped film designs and process flow sheet technologies, are also under continuous development. Aiming at the high-doped piezoelectric film, particularly the high-scandium-doped aluminum nitride film, the quality of the film deposited in the original aluminum nitride film process is poor due to the addition of metal elements, and the film is mainly characterized in that the grain boundary precipitation of the scandium-doped aluminum nitride film is serious, the roughness of the surface of the piezoelectric ceramic is large, and the surface of the piezoelectric ceramic is rugged in microscopic view. Disclosure of Invention The embodiment of the application aims to provide a MEMS piezoelectric device, which has the advantages that the deposition quality of a highly doped piezoelectric layer is good, the problem of grain boundary precipitation is less, and each layer of a MEMS system structure is flat, so that the device performance is stable and excellent. In one aspect of the embodiment of the application, the MEMS piezoelectric device comprises a substrate with a cavity, wherein at least one first electrode layer is laminated on the substrate in the area of the cavity, at least one second electrode layer is laminated on the substrate in the area outside the cavity, the second electrode layer is at least positioned on one side of the cavity, the second electrode layer and the first electrode layer which are arranged at intervals are arranged on the same layer, and piezoelectric layers are formed on the second electrode layer and the first electrode layer. The MEMS piezoelectric device provided by the embodiment of the application can solve the problem of grain boundary precipitation of the high-doped piezoelectric layer, so that the piezoelectric layer grown in the non-effective area has enough smoothness, other structural layers which are continuously deposited above the piezoelectric layer in the non-effective area, and metal wires, pads and the like which are distributed above the piezoelectric layer have good smoothness, and the MEMS manufacturing precision is higher. Drawings In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments of the present application will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and should not be considered as limiting the scope, and other related drawings can be obtained according to these drawings without inventive effort for a person skilled in the art. FIG. 1 is a diagram showing one of the surface topography states of a highly doped piezoelectric layer fabricated by prior art design; FIG. 2 is a schematic diagram of a structure of a conventional MEMS piezoelectric device; FIG. 3 is a schematic diagram of a MEMS piezoelectric device according to an embodiment of the present application; FIG. 4 is a schematic diagram of a second embodiment of a MEMS piezoelectric device; FIG. 5 is a graph showing the comparison of the piezoelectric layer deposition effect of the MEMS piezoelectric device provided in the present embodiment with the piezoelectric layer of the prior art; FIG. 6 is a second surface topography of a highly doped piezoelectric layer fabricated by prior art design; FIG. 7 is a third surface topography of a highly doped piezoelectric layer fabricated by prior art design; Fig. 8 is a topography diagram showing a practical state of deposition of a piezoelectric layer of a MEMS piezoelectric device according to an embodiment of the present application. The icons