Micro-electromechanical devices and methods of fabricating thereof

Abstract

An electromechanical device includes a support structure formed by attaching inner surfaces of second and third substrates to a first substrate. The support structure includes at least one cavity between the second and third layers. An electromechanical active element is provided on an outer surface of at least one of the second or third layers.

1 . A device comprising:
 a support structure including
 a first layer comprising a single crystal material having first and second surfaces, 
 second and third layers having opposing inner and support surfaces, wherein the inner surfaces of the second and third layers are attached to first and second surfaces of the first layer to form a three layered sandwich, and 
 at least one cavity in the support structure disposed between inner surfaces of the second and third layers; and 
   an electromechanical active element on at least one of the support surfaces of the second and third layers.   
   
   
       2 . The device of  claim 1  wherein the active element comprises an active film of a piezoelectric or electrostrictive material. 
   
   
       3 . The device of  claim 2  wherein the active film of a piezoelectric or electrostrictive material has a composition at a morphotropic phase boundary (MPB). 
   
   
       4 . The device of  claim 1  wherein active elements are provided on support surfaces of the second and third layers. 
   
   
       5 . The device of  claim 4  wherein the active element comprises active films of a piezoelectric or electrostrictive material having a composition at morphotropic phase boundary (MPB). 
   
   
       6 . The device of  claim 1  wherein the single crystal material comprises single crystal silicon. 
   
   
       7 . The device of  claim 6  wherein the first, second and third layers are attached by anodic bonding. 
   
   
       8 . The device of  claim 7  wherein the second and third layers comprise glass, silicon, ceramic or a combination thereof. 
   
   
       9 . The device of  claim 6  wherein the single crystal silicon is (110)-oriented and a <110> crystallographic direction is parallel to the sandwich direction of the three layered sandwich. 
   
   
       10 . The device of  claim 9  wherein the second and third layers comprise glass, silicon, ceramic or a combination thereof. 
   
   
       11 . The device of  claim 1  wherein the single crystal material comprises a (110)-oriented crystal and a <110> crystallographic direction is parallel to the sandwich direction of the three layered sandwich. 
   
   
       12 . The device of  claim 11  wherein the second and third layers comprise glass, silicon, ceramic or a combination thereof. 
   
   
       13 . The device of  claim 1  wherein opposing side surfaces of the three layered sandwich which are perpendicular to the support surfaces comprise cut surfaces to produce a plurality of devices in parallel. 
   
   
       14 . The device of  claim 13  wherein the single crystal material having a <110> crystallographic direction parallel to a sandwich direction of the three layered sandwich, and the opposing side surfaces of the single crystal materials are parallel with (111) crystallographic plane. 
   
   
       15 . The device of  claim 13  wherein the second and third layers comprise glass, silicon, ceramic or a combination thereof. 
   
   
       16 . The device of  claim 13  wherein:
 the first layer comprises a single crystal wafer having elongated primary slots through first and second surfaces;   the second and third layers comprise wafers with inner surfaces attached to first and second surfaces of the first layer to form a wafer sandwich stack; and   a plurality of devices are formed when the wafer sandwich stack is diced.   
   
   
       17 . The device of  claim 16  wherein the second and third layers comprise glass, silicon, ceramic or a combination thereof. 
   
   
       18 . A device comprising:
 a support structure including
 a first layer comprising a single crystal material having first and second surfaces, 
 second and third layers having opposing inner and support surfaces, wherein the inner surfaces of the second and third layers are attached to first and second surfaces of the first layer, 
 at least one cavity in the support structure disposed between inner surfaces of the second and third layers, and 
 wherein opposing side surfaces of the support structure which the cavity extends through comprise cut surfaces to produce a plurality of devices in parallel; and 
   an active element on at least one of the support surfaces of the second and third layers.   
   
   
       19 . A device comprising:
 a support structure including
 a first layer having first and second surfaces, 
 second and third layers having opposing inner and support surfaces, wherein the inner surfaces of the second and third layers are attached to first and second surfaces of the first layer, and 
 at least one cavity in the support structure disposed between inner surfaces of the second and third layers, wherein the cavity is formed by forming an opening through first and second surfaces of the first layer using an etching process prior to attachment of the second and third layers to the first layer; and 
   an active element on at least one of the support surfaces of the second and third layers.   
   
   
       20 . The device of  claim 19  wherein the active element comprises an active film of a piezoelectric or electrostrictive material, and the piezoelectric or electrostrictive films are deposited on both of the support surfaces of the second and third layers.