Method and product for fabricating a resonant-bridge microaccelerometer
First Claim
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1. A method for forming an accelerometer comprising the following steps:
- providing a silicon substrate;
forming a buried layer in said silicon substrate;
forming a predetermined proof mass of appropriate lateral dimensions on said silicon substrate symmetrically disposed generally over said buried layer;
removing silicon from said silicon substrate, so as to delineate a pattern which generally corresponds to said lateral dimensions of said predetermined proof mass and so as to delineate a plurality of microbridges; and
removing said buried layer in said silicon substrate so as to form a cavity generally everywhere therebetween said proof mass and said microbridges, and said silicon substrate.
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Abstract
A resonant bridge microaccelerometer is formed using patterned Silicon-on-Insulator (SOI) material. A buried layer is formed in the silicon substrate using preferably oxygen ion implanting techniques. A predetermined proof mass is subsequently formed by selective deposition of an appropriate material on an epitaxially grown layer of silicon generally over the buried layer. The buried layer is subsequently removed by a hydrofluoric acid etch, thereby forming a gap generally everywhere therebetween the proof mass and the supporting silicon substrate, and delineating the resonant microbridges within the microaccelerometer.
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Citations
14 Claims
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1. A method for forming an accelerometer comprising the following steps:
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providing a silicon substrate; forming a buried layer in said silicon substrate; forming a predetermined proof mass of appropriate lateral dimensions on said silicon substrate symmetrically disposed generally over said buried layer; removing silicon from said silicon substrate, so as to delineate a pattern which generally corresponds to said lateral dimensions of said predetermined proof mass and so as to delineate a plurality of microbridges; and removing said buried layer in said silicon substrate so as to form a cavity generally everywhere therebetween said proof mass and said microbridges, and said silicon substrate. - View Dependent Claims (2, 3, 4, 5, 13, 14)
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6. A method for forming an accelerometer comprising the following steps:
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providing a silicon substrate; forming a buried layer in said silicon substrate; epitaxially growing a silicon layer from said silicon substrate generally over said buried layer; removing silicon from said epitaxially grown silicon layer, so as to delineate a pattern which generally corresponds to said lateral dimensions of said predetermined proof mass and so as to delineate a plurality of microbridges; forming a layer of silicon dioxide on said epitaxially grown silicon layer and photolithographically delineating said silicon dioxide layer so as to expose at least one region of said epitaxially grown silicon layer; forming a predetermined proof mass of appropriate lateral dimensions on said exposed region of said epitaxially grown silicon layer by depositing an appropriate material in those delineated regions of said silicon dioxide layer, said predetermined proof mass being symmetrically disposed generally over said buried layer; removing said silicon dioxide layer; and removing said buried layer in said silicon substrate so as to form a cavity generally everywhere therebetween said proof mass and said microbridges, and said silicon substrate. - View Dependent Claims (7, 8, 9, 10)
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11. A method for forming an accelerometer comprising the following steps:
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providing a single crystal silicon substrate; forming a buried layer in said silicon substrate; epitaxially growing a n+ silicon layer from said silicon substrate generally over said buried layer; removing silicon from said epitaxially grown silicon layer, so as to delineate a pattern which will generally correspond to the lateral dimensions of a predetermined proof mass and a plurality of microbridges; thermally growing a layer of silicon dioxide on said epitaxially grown silicon layer and photolithographically delineating said silicon dioxide layer so as to expose at least one region of said epitaxially grown silicon layer; forming a predetermined proof mass comprising gold of appropriate lateral dimensions on said exposed regions of said epitaxially grown silicon layer by depositing an appropriate material in those delineated regions of said silicon dioxide layer, said predetermined proof mass being symmetrically disposed generally over said buried layer; removing said silicon dioxide layer; and removing said buried layer in said silicon substrate using a hydrofluoric acid etch so as to form a cavity generally everywhere therebetween said proof mass and said microbridges, and said silicon substrate. - View Dependent Claims (12)
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Specification