Process for manufacturing buried channels and cavities in semiconductor material wafers
First Claim
1. A process for manufacturing unfilled buried cavities in semiconductor material wafers, comprising:
- forming, on a monocrystalline body of semiconductor material, a nucleus region surrounded by a protective structure;
forming a cavity in said monocrystalline body beneath said nucleus region;
removing at least a top portion of said protective structure; and
growing an epitaxial layer over the cavity on said monocrystalline body and said nucleus region.
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Accused Products
Abstract
A process of forming on a monocrystalline-silicon body an etching-aid region of polycrystalline silicon; forming, on the etching-aid region a nucleus region of polycrystalline silicon surrounded by a protective structure having an opening extending as far as the etching-aid region; TMAH-etching the etching-aid region and the monocrystalline body to form a tub-shaped cavity; removing the top layer of the protective structure; and growing an epitaxial layer on the monocrystalline body and the nucleus region. The epitaxial layer, of monocrystalline type on the monocrystalline body and of polycrystalline type on the nucleus region, closes upwardly the etching opening, and the cavity is thus completely embedded in the resulting wafer.
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Citations
20 Claims
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1. A process for manufacturing unfilled buried cavities in semiconductor material wafers, comprising:
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forming, on a monocrystalline body of semiconductor material, a nucleus region surrounded by a protective structure;
forming a cavity in said monocrystalline body beneath said nucleus region;
removing at least a top portion of said protective structure; and
growing an epitaxial layer over the cavity on said monocrystalline body and said nucleus region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
forming, on said monocrystalline body and said etching-aid region, a layer stack comprising a first etch-shielding layer, a polycrystalline-silicon layer, and a second etch-shielding layer;
forming, in said layer stack and on said etching-aid region, a window having side delimiting walls; and
coating said side delimiting walls of said window with a coating region, forming an opening for etching said monocrystalline body.
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7. The process of claim 6 wherein said first and second etch-shielding layers and said coating region are of silicon nitride.
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8. The process of claim 7, further comprising forming a thermal oxide layer beneath said first and second etch-shielding layers and forming thermal oxide regions beneath said coating region.
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9. The process of claim 1, further comprising forming a protective region on walls of said cavity before removing a top portion of said protective structure.
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10. The process of claim 9 wherein forming a protective region comprises thermally oxidizing said walls of said cavity.
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11. The process of claim 1 wherein growing an epitaxial layer comprises forming a monocrystalline region on said monocrystalline body, and a polycrystalline region on said nucleus region.
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12. A process for manufacturing unfilled buried cavities in semiconductor material, comprising:
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forming a protective structure on a substrate of semiconductor material, the protective structure having an opening formed therein;
forming a cavity in the substrate below the protective structure and in communication with the opening; and
forming an epitaxial layer over the protective structure to cover the opening. - View Dependent Claims (13, 14, 15, 16)
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17. A process for manufacturing buried cavities and semiconductor wafers, comprising:
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forming an etching-aid region directly on a monocrystalline body of semiconductor material, the etching-aid region being formed of polycrystalline silicon;
forming a nucleus region surrounded by a protective structure that covers the etching-aid region;
forming a cavity in the monocrystalline body beneath the nucleus region;
removing at least a top portion of the protective structure; and
growing an epitaxial layer on the monocrystalline body and the nucleus region.
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18. A process for manufacturing buried cavities in semiconductor material wafers, comprising:
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forming, on a monocrystalline body of semiconductor material, a nucleus region surrounded by a protective structure;
forming a cavity in said monocrystalline body beneath said nucleus region;
removing at least a top portion of said protective structure; and
growing an epitaxial layer on said monocrystalline body and said nucleus region, comprising forming a monocrystalline region on the monocrystalline body and a polycrystalline region on the nucleus region.
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19. A process for manufacturing buried cavities in semiconductor material, comprising:
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forming a protective structure on a substrate of semiconductor material, the protective structure having an opening formed therein, comprising forming on the substrate an etching-aid region and a layer stack, the etching-aid region comprising a polycrystalline silicon layer, and the layer stack comprising a first etch-shielding layer, a polycrystalline-silicon layer on the first etch-shielding layer, and a second etch-shielding layer on the polycrystalline-silicon layer;
forming a cavity in the substrate below the protective structure and in communication with the opening; and
forming an epitaxial layer over the protective structure to cover the opening.
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20. A process for manufacturing buried cavities in semiconductor material, comprising:
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forming a protective structure on a substrate of semiconductor material, the protective structure having an opening formed therein, forming the protective structure for the comprising forming on the substrate an etching-aid region and a layer stack, the etching-aid region comprising a polycrystalline silicon layer, and the layer stack comprising a first etch-shielding layer, a polycrystalline-silicon layer on the first etch-shielding layer, and a second etch-shielding layer on the polycrystalline-silicon layer, and further forming a coating on the layer stack and on walls of the opening;
forming a cavity in the substrate below the protective structure and in communication with the opening; and
forming an epitaxial layer over the protective structure to cover the opening.
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Specification