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US 5,539,241 AGranted
Monolithic passive component
AssigneeThe Regents of the University of California
InventorsAsad A. Abidi, James Y.-C. Chang
Life of this patent
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Abstract
An integrated circuit having a monolithic device such as an inductor suspended over a pit in the substrate to reduce parasitic capacitances and enhance the self-resonant frequency of the inductor.
Claims32
A monolithic integrated circuit, comprising:
- a silicon substrate having a surface and provided with a pit which defines a space located below the substrate surface and which opens at the substrate surface;
- a plurality of semiconductor circuit elements formed on the substrate;
- an insulating layer formed on the substrate and extending across the pit;
- and
- a planar spiral inductor positioned over the pit so that the inductor is spaced from the underlying substrate by the pit and supported by the insulating layer, said inductor being one of electrically or mechanically coupled to at least one of the semiconductor circuit elements.
2 more elements
A process for forming an integrated RF tuned amplifier circuit, comprising the steps of:
- forming a plurality of transistors on a silicon substrate;
- forming an oxide layer on the substrate and at least a portion of the transistor;
- forming a metallization layer on the oxide layer, said metallization layer including a spiral-shaped inductor and a plurality of interconnections which interconnect the transistors and the inductor as an RF amplifier circuit;
- applying an etchant through openings in the oxide layer to remove a portion of the substrate beneath the inductor and the oxide layer to form a pit beneath the inductor and the oxide layer to reduce parasitic capacitance between the inductor and the underlying substrate.
1 more element
A monolithic integrated high frequency circuit, comprising:
- a silicon substrate having a surface and provided with a pit which defines a space located below the substrate surface and which opens at the substrate surface;
- a plurality of semiconductor circuit elements formed on the substrate;
- an insulating layer formed on the substrate and extending across the pit;
- and
- a spiral inductor having a planar portion positioned over the pit so that the inductor is spaced from the underlying substrate by the pit and supported by the insulating layer, said inductor being electrically connected to at least one of the semiconductor circuit elements to form the integrated high frequency circuit.
2 more elements
A process for forming a monolithic integrated high frequency circuit, comprising the steps of:
- providing a substrate having a surface;
- forming an insulating layer on the substrate surface;
- forming an inductor on the insulating layer so that the inductor is supported by the insulating layer;
- and
- removing material from a portion of the substrate to form a pit in the substrate which is located beneath the inductor, thereby reducing parasitic capacitance between the inductor and the substrate, while the inductor remains supported by portions of the substrate surface which surround the pit.
2 more elements
Dependencies are inferred from the claim text.