Microfabricated ultrasonic immersion transducer

DETAILED DESCRIPTION It is an object of the present invention to provide an immersion microfabricated ultrasonic transducer.
It is a further object of the present invention to provide a method of fabricating microfabricated ultrasonic transducers having reproducible sealed membranes spaced from an underlying conductive substrate.
It is a further object of the present invention to provide an ultrasonic immersion sealed membranes microfabricated ultrasonic transducer having membranes which can be of selected sizes and shapes.
It is a further object of the present invention to provide robust vacuum sealed ultrasonic transducers which can operate immersed in liquid or gas.
It is another object of the present invention to provide microfabricated membranes closely spaced from an underlying substrate and supported at their edges by a layer of insulating material to define with said substrate an evacuated cavity and to a method of fabricating such sealed membranes.
In accordance with the present invention, there is provided a microfabricated transducer which includes a conductive substrate and a sealed membrane supported in close proximity to the substrate by an insulating film or layer with the support, substrate and membrane defining, a sealed, evacuated cavity.
The invention also relates to a method of forming such transducer employing conventional semiconductor processing techniques.