Piezoelectric micromachined ultrasonic transducer (pmut)

Abstract

A Piezoelectric Micromachined Ultrasonic Transducer (PMUT) device is provided. The PMUT includes a substrate and an edge support structure connected to the substrate. A membrane is connected to the edge support structure such that a cavity is defined between the membrane and the substrate, where the membrane is configured to allow movement at ultrasonic frequencies. The membrane includes a piezoelectric layer and first and second electrodes coupled to opposing sides of the piezoelectric layer. An interior support structure is disposed within the cavity and connected to the substrate and the membrane.

What is claimed is: 
     
         1 . A Piezoelectric Micromachined Ultrasonic Transducer (PMUT) device comprising:
 a substrate;   an edge support structure connected to the substrate;   a membrane connected to the edge support structure such that a cavity is defined between the membrane and the substrate, the membrane configured to allow movement at ultrasonic frequencies, the membrane comprising:
 a piezoelectric layer; and 
 first and second electrodes coupled to opposing sides of the piezoelectric layer; and 
   an interior support structure disposed within the cavity and connected to the substrate and the membrane.   
     
     
         2 . The PMUT device of  claim 1 , further comprising:
 a second interior support structure disposed within the cavity and connected to the substrate and the membrane.   
     
     
         3 . The PMUT device of  claim 1 , wherein the interior support structure is non-centrally positioned within the cavity. 
     
     
         4 . The PMUT device of  claim 1 , wherein the first electrode defines a continuous layer. 
     
     
         5 . The PMUT device of  claim 1 , wherein the first electrode is a patterned layer. 
     
     
         6 . The PMUT device of  claim 1 , the membrane further comprising:
 a mechanical support layer connected to the first electrode.   
     
     
         7 . The PMUT device of  claim 6 , wherein the mechanical support layer defines a continuous layer. 
     
     
         8 . The PMUT device of  claim 6 , wherein the mechanical support layer is a patterned layer. 
     
     
         9 . The PMUT device of  claim 1 , wherein the piezoelectric layer defines a continuous layer. 
     
     
         10 . The PMUT device of  claim 1 , wherein the piezoelectric layer is a patterned layer. 
     
     
         11 . The PMUT device of  claim 1 , wherein the second electrode extends into the cavity and defines an area between the edge support structure and the interior support structure. 
     
     
         12 . The PMUT device of  claim 1 , wherein the interior support structure is connected to the piezoelectric layer of the membrane. 
     
     
         13 . The PMUT device of  claim 1 , wherein the PMUT device is substantially circular such that the edge support structure and the membrane are substantially circular. 
     
     
         14 . The PMUT device of  claim 1 , wherein the PMUT device is substantially square-shaped such that the edge support structure and the membrane are substantially square-shaped. 
     
     
         15 . The PMUT device of  claim 1 , wherein at least one of the first electrode and the second electrode is electrically coupled through the interior support structure. 
     
     
         16 . The PMUT device of  claim 1 , the membrane further comprising:
 a third electrode coupled to the piezoelectric layer on an opposing side of the piezoelectric layer as the first electrode.   
     
     
         17 . The PMUT device of  claim 1 , wherein the edge support structure is connected to an electric potential. 
     
     
         18 . The PMUT device of  claim 1 , wherein the substrate comprises a CMOS logic wafer. 
     
     
         19 . A Piezoelectric Micromachined Ultrasonic Transducer (PMUT) array comprising:
 a plurality of PMUT devices, wherein at least one PMUT device of the plurality of PMUT devices comprises:
 a substrate; 
 an edge support structure connected to the substrate, wherein the edge support structure is connected to an electric potential; 
 a membrane connected to the edge support structure such that a cavity is defined between the membrane and the substrate, the membrane configured to allow movement at ultrasonic frequencies, the membrane comprising:
 a piezoelectric layer; 
 first and second electrodes coupled to opposing sides of the piezoelectric layer; and 
 a mechanical support layer connected to the first electrode; and 
 
 an interior support structure disposed within the cavity and connected to the substrate and the membrane. 
   
     
     
         20 . An image sensing system comprising:
 a plurality of Piezoelectric Micromachined Ultrasonic Transducer (PMUT) devices, wherein at least one PMUT device of the plurality of PMUT devices comprises:
 a substrate; 
 an edge support structure connected to the substrate; 
 a membrane connected to the edge support structure such that a cavity is defined between the membrane and the substrate, the membrane configured to allow movement at ultrasonic frequencies, the membrane comprising:
 a piezoelectric layer; 
 first and second electrodes coupled to opposing sides of the piezoelectric layer; and 
 a mechanical support layer connected to the first electrode; and 
 
 an interior support structure disposed within the cavity and connected to the substrate and the membrane; and 
   control logic electrically coupled to the plurality of PMUT devices, the control logic for sensing an image.