Silicon-on-insulator islands
AssigneeMicron Technology, Inc.
InventorWendell P. Noble
Life of this patent
Estimating the term…
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.
Claims8
A silicon-on-insulator structure on a supporting surface of a silicon substrate, comprising:
- a fully undercut silicon island electrically isolated from the silicon substrate and having one or more lateral surfaces substantially perpendicular to the supporting surface of the silicon substrate;
- a silicon oxide bar on and extending from the supporting surface of the silicon substrate and having one or more lateral surfaces, each substantially perpendicular to the supporting surface of the silicon substrate and with at least one of the lateral surfaces attached to one of the lateral surfaces of the fully undercut silicon island and thereby holding the fully undercut silicon island above the supporting surface to define a vertical gap fully separating the silicon island and the supporting surface.
An integrated-circuit-processing structure comprising:
- a semiconductive island having top and bottom surfaces and first and second lateral surfaces;
- an oxide layer on the top surface and having first and second lateral surfaces substantially perpendicular to the top surface of the semiconductive island;
- a silicon-nitride layer on the oxide layer and having first and second lateral surfaces substantially perpendicular to the top surface of the semiconductive island;
- a silicon oxide structure having first and second lateral surfaces and a bottom surface generally perpendicular to the first and second lateral surfaces, with the first lateral surface abutting the first lateral surfaces of the semiconductive island, the oxide layer, and the silicon-nitride layer;
- a silicon nitride sidewall abutting the second lateral surfaces of the semiconductive island, the oxide layer, and the silicon-nitride layer;
- and
- a semiconductive substrate having a top surface abutting the bottom surface of the silicon oxide structure, and fully separated from the bottom surface of the semiconductive island to define a vertical gap fully separating the bottom surface of the semiconductive island and the top surface of the semiconductive substrate.
An integated-circuit structure comprising:
- a semiconductive substrate having a top surface;
- a semiconductive island having top and bottom surfaces and a peripheral lateral surface between the top and bottom surfaces, with none of the surfaces of the semiconductive island contacting the semiconductive substrate;
- and
- an insulative pillar attached to the semiconductive substrate and having a lateral surface attached to the peripheral lateral surface of the semiconductive island for fully supporting the semiconductive island above a gap over the top surface of the semiconductive substrate.
A structure comprising:
- a semiconductive substrate having a top surface;
- an insulative pillar attached to and extending from the top surface of the substrate;
- and
- a semiconductive island cantilevered off a lateral surface of the insulative pillar, the island having a bottom surface with no support structures extending from the top surface of the substrate to the bottom surface of the island to facilitate low-stress introduction of oxide between the top and bottom surfaces.
Dependencies are inferred from the claim text.