Semiconductor device
AssigneeSanyo Electric Co., Ltd.
InventorsShigeaki Okawa, Toshiyuki Ohkoda
Life of this patent
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Abstract
The object of the present invention is to provide a semiconductor device, which is suitable for use to connect electric condenser microphones. A semiconductor device, comprises: a conductivity-type substrate; an epitaxial layer formed on top of the substrate; island regions separating the epitaxial layer; an input transistor formed on one of the island regions; an insulation layer covering the surface of the input transistor layer; an expansion electrode formed above the insulation layer so as to provide an electrical connection to an input terminal of the input transistor; and resistivity of the epitaxial layer formed below the expansion electrode being in a range of 1000˜5,000 Ω·cm.
Claims12
A semiconductor device for use with an electric condenser microphone, said semiconductor device comprising:
- a substrate having a first conductivity type;
- an epitaxial layer formed on top of said substrate, said epitaxial layer having a second conductivity type and including separation regions;
- an island region formed in said epitaxial layer between said separation regions;
- a junction field-effect transistor formed in said island region, said junction field-effect transistor having a gate electrode;
- an insulating film formed on said epitaxial layer;
- and
- an expansion electrode formed on said insulating film and arranged so as to be connectable to the electric condenser microphone, said expansion electrode being connected to said gate electrode of said junction field-effect transistor,
- wherein a resistivity of said epitaxial layer formed below said expansion electrode is in a range of 100˜5,000 Ω·cm.
A semiconductor device for use with an electric condenser microphone, said semiconductor device comprising:
- a substrate having a first conductivity type;
- an epitaxial layer formed on top of said substrate, said epitaxial layer having a second conductivity type and including separation regions;
- an island region formed in said epitaxial layer between said separation regions;
- a junction field-effect transistor formed in said island region, said junction field-effect transistor having a gate electrode;
- an insulating film formed on said epitaxial layer;
- and
- an expansion electrode formed on said insulating film and arranged so as to be connectable to the electric condenser microphone, said expansion electrode being connected to said gate electrode of said junction field-effect transistor,
- wherein a resistivity of said epitaxial layer formed below said expansion electrode is at least 100 Ω·cm.
Dependencies are inferred from the claim text.