Application of a strain-compensated heavily doped etch stop for silicon structure formation
First Claim
1. A method of making a silicon micromechanical structure, comprising the steps of:
- forming a lightly doped silicon substrate having a first and second side and having less than 5×
1019 cm−
3 boron therein;
placing a p+ layer on the first side of said substrate, said p+ having a boron content of greater than 7×
1019 cm−
3 and a germanium content of about 1×
1021 cm−
3;
forming a mask on the second side for etching a predetermined pattern;
etching said second side to said p+ layer; and
depositing an insulator on said p+ layer and fabricating an electronic component on said insulator.
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Accused Products
Abstract
A method of making a silicon micromechanical structure, from a lightly doped silicon substrate having less than <5×1019 cm−3 boron therein. A p+ layer having a boron content of greater than 7×1019 cm−3 and a germanium content of about 1×1021 cm−3 is placed on the substrate. A mask is formed on the second side, followed by etching to the p+ layer. An insulator is put on the p+ layer and an electronic component is fabricated thereon. Preferred micromechanical structures are pressure sensors, cantilevered accelerometers, and dual web biplane accelerometers. Preferred electronic components are dielectrically isolated piezoresistors and resonant microbeams. The method may include the step of forming a lightly doped layer on the p+ layer to form a buried p+ layer prior to etching.
15 Citations
36 Claims
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1. A method of making a silicon micromechanical structure, comprising the steps of:
-
forming a lightly doped silicon substrate having a first and second side and having less than 5×
1019 cm−
3 boron therein;
placing a p+ layer on the first side of said substrate, said p+ having a boron content of greater than 7×
1019 cm−
3 and a germanium content of about 1×
1021 cm−
3;
forming a mask on the second side for etching a predetermined pattern;
etching said second side to said p+ layer; and
depositing an insulator on said p+ layer and fabricating an electronic component on said insulator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 19)
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10. A method of making a silicon micromechanical structure, comprising the steps of:
-
forming a lightly doped silicon substrate having a first and second side and having less than 5×
1019 cm−
3 boron therein;
placing a p+ layer on the first side of said substrate, said p+ having a boron content of greater than 7×
1019 cm−
3 and a germanium content of about 1×
1021 cm−
3;
forming a lightly doped layer on said p+ layer to form a buried p+ layer;
forming a mask on the second side for etching a predetermined pattern;
etching said second side to said buried p+ layer; and
depositing an insulator on said lightly doped layer and fabricating an electronic component on said insulator. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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Specification