Multilayer MEMS cantilevers

A method for producing a cantilever or membrane comprising the steps of:

• providing a first wafer including a first layer deposited on a first external surface of the wafer and a second layer deposited on a second external surface of the wafer;
• providing a second wafer including a first layer deposited on a first external surface of the wafer and a second layer deposited on a second external surface of the wafer;
• forming a first structure by depositing a third layer comprising a material having an elastic modulus inferior to that of the first and second layer on the first layer of the first wafer;
• forming a second structure by depositing a third layer comprising a material having an elastic modulus inferior to that of the first and second layer on the first layer of the second wafer;
• wafer bonding the first and second structures together by combining the third layer of the first structure with the third layer of the second structure,
• partially removing the exposed second layer on a first external surface of the bonded structure to expose the first wafer material and create a first etch mask window, and partially removing the exposed second layer on a second external surface of the bonded structure to expose the second wafer material and create a second etch mask window;
• etching the exposed first wafer material and the exposed second wafer material to remove part of the first and second wafer material and expose a beam including the combined third sandwiched between the first layers;
• depositing an etch stop and support layer on the second wafer material and the first layer of the second wafer;
• etching through the beam to divide the bean in two parts;
• and
• removing the etch stop and support layer.

An AFM cantilever comprising:

• a body,
• an elongated beam attached to the body,
• wherein the elongated beam includes:
• a first layer comprising a first material,
• a second layer comprising a second material having an elastic modulus different to that of the first material,
• a third layer comprising a third material having an elastic modulus different to that of the first material,
• the first layer being sandwiched between the second layer and the third layer,
• wherein inherent or intrinsic material damping of the first material dominates a response time of the cantilever, or the first material has an elastic modulus inferior to that of the second and third material.