Silicon-on-insulator islands
AssigneeMicron Technology, Inc.
InventorWENDELL P NOBLE
Life of this patent
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Abstract
Silicon-on-insulator (SOI) islands are formed in a silicon substrate. A first set of trenches is formed in the silicon substrate, leaving laterally-isolated rows of silicon between the trenches. The first set of trenches is then filled with silicon oxide. A second set of trenches is then formed in the silicon substrate at a direction orthogonal to the first set of trenches. Silicon nitride is then deposited over the sidewalls of the second set of trenches. An isotropic chemical etch is then used to fully undercut narrow the laterally-isolated rows of silicon between the second set of trenches to form evacuated regions beneath silicon islands. A subsequent oxidation step fills the evacuated regions to form the SOI islands.
Claims31
A method of fabricating a silicon-on-insulator structure on a supporting silicon substrate, comprising the steps of:
- defining fully undercut silicon islands in the silicon substrate supported by lateral silicon oxide bars extending to the silicon substrate;
- and
- forming silicon oxide between the silicon islands and the silicon substrate.
A method of fabricating a silicon-on-insulator structure on a supporting silicon substrate having a pad structure formed thereon, comprising the steps of:
- defining a first set of trenches in the silicon substrate, the first set of trenches extending through the pad structure to form laterally-isolated bars of silicon in the silicon substrate;
- filling the first set of trenches with silicon oxide to form silicon oxide bars;
- defining a second set of trenches in the substrate, wherein the second set of trenches is defined by sidewalls and extend through the pad structure in a direction orthogonal to the first set of trenches to form silicon islands defined by the silicon oxide bars and the second set of trenches;
- forming a silicon nitride layer on the sidewalls defining the second set of trenches;
- undercutting the laterally-isolated bars of silicon between the second set of trenches to define evacuated regions underneath the silicon islands;
- and
- filling the evacuated regions with silicon oxide.
A method of fabricating a silicon-on-insulator structure on a supporting silicon substrate having a pad structure formed thereon, comprising the steps of:
- forming laterally-isolated silicon oxide bars in the silicon substrate;
- defining a set of trenches in the substrate, wherein the set of trenches is defined by sidewalls and extend through the pad structure to form silicon islands defined by the laterally-isolated silicon oxide bars and the set of trenches;
- masking the sidewalls defining the set of trenches with an oxidation barrier mask;
- undercutting the laterally-isolated bars of silicon between the set of trenches to define evacuated regions underneath the silicon islands;
- and
- filling the evacuated regions with silicon oxide.
A silicon-on-insulator structure on a supporting silicon substrate, comprising:
- a fully undercut silicon island in the silicon substrate, the fully undercut silicon island is supported by lateral silicon oxide bars extending to the silicon substrate;
- and
- silicon oxide between the silicon island and the silicon substrate.
A silicon-on-insulator structure on a supporting silicon substrate, comprising:
- a plurality of silicon islands in the silicon substrate;
- chemical vapor deposition silicon oxide extending from the top of the silicon-on-insulator structure to the silicon substrate, vertically isolating the silicon islands;
- and
- thermal silicon oxide between the silicon islands and the silicon substrate, horizontally isolating the silicon islands.
Dependencies are inferred from the claim text.