Capacitive micromachined ultrasound transducer fabricated with epitaxial silicon membrane
First Claim
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1. A method for fabricating a capacitive micromachined ultrasound transducer cell, the method comprising:
- forming a cavity on a topside of a first substrate, wherein the cavity is defined by a plurality of support posts;
disposing a diaphragm on the plurality of support posts to form a composite structure with a top portion having a gap between the lower electrode and the diaphragm, wherein the diaphragm comprises one of a first epitaxial layer or a first polysilicon layer wherein the top portion comprises disposing one of the epitaxial layer or the first polysilicon layer on a second substrate, wherein one of the epitaxial layer or the polysilicon layer and the second substrate are oppositely doped and wherein a doping level in the first epitaxial layer is different than a doping level in the substrate; and
disposing a stress reducing material comprises geranium in one of the first epitaxial layer or the first polysilicon layer.
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Abstract
A capacitive micromachined ultrasound transducer (cMUT) cell is presented. The cMUT cell includes a lower electrode. Furthermore, the cMUT cell includes a diaphragm disposed adjacent to the lower electrode such that a gap having a first gap width is formed between the diaphragm and the lower electrode, wherein the diaphragm comprises one of a first epitaxial layer or a first polysilicon layer. In addition, a stress reducing material is disposed in the first epitaxial layer.
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9 Claims
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1. A method for fabricating a capacitive micromachined ultrasound transducer cell, the method comprising:
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forming a cavity on a topside of a first substrate, wherein the cavity is defined by a plurality of support posts; disposing a diaphragm on the plurality of support posts to form a composite structure with a top portion having a gap between the lower electrode and the diaphragm, wherein the diaphragm comprises one of a first epitaxial layer or a first polysilicon layer wherein the top portion comprises disposing one of the epitaxial layer or the first polysilicon layer on a second substrate, wherein one of the epitaxial layer or the polysilicon layer and the second substrate are oppositely doped and wherein a doping level in the first epitaxial layer is different than a doping level in the substrate; and disposing a stress reducing material comprises geranium in one of the first epitaxial layer or the first polysilicon layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification