Semiconductor pressure sensor
AssigneeMitsubishi Electric Corporation
InventorKimitoshi Sato
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Abstract
A semiconductor pressure sensor includes a fixed electrode placed at a principal surface of a semiconductor substrate, and a diaphragm movable through an air gap in a thickness direction of the semiconductor substrate at least in an area where the diaphragm is opposed to the fixed electrode. The diaphragm includes: a movable electrode; a first insulation film placed closer to the air gap with respect to the movable electrode; a second insulation film placed opposite to the air gap with respect to the movable electrode, the second insulation film being of a same film type as the first insulation film; and a shield film that sandwiches the second insulation film with the movable electrode.
Claims6
A semiconductor pressure sensor, comprising:
- a fixed electrode placed at a principal surface of a semiconductor substrate;
- and
- a diaphragm movable through an air gap in a thickness direction of said semiconductor substrate at least in an area where said diaphragm is opposed to said fixed electrode,
- said diaphragm including:
- a movable electrode;
- a first insulation film placed closer to said air gap with respect to said movable electrode;
- a second insulation film placed opposite to said air gap with respect to said movable electrode, said second insulation film being of a same film type as said first insulation film;
- and
- a shield film that sandwiches said second insulation film with said movable electrode, wherein
- said movable electrode includes a first polysilicon layer having a compressive internal stress, a second polysilicon layer having a tensile internal stress, and a third polysilicon layer having a compressive internal stress, said first polysilicon layer, said second polysilicon layer, and said third polysilicon layer being laminated in said thickness direction in a stated order from said fixed electrode, and
- said shield film is a fourth polysilicon layer having a compressive internal stress.
A semiconductor pressure sensor, comprising:
- a fixed electrode placed at a principal surface of a semiconductor substrate;
- and
- a diaphragm movable through an air gap in a thickness direction of said semiconductor substrate at least in an area where said diaphragm is opposed to said fixed electrode,
- said diaphragm including:
- a movable electrode;
- a first insulation film placed closer to said air gap with respect to said movable electrode;
- a second insulation film placed opposite to said air gap with respect to said movable electrode, said second insulation film being of a same film type as said first insulation film;
- and
- a shield film that sandwiches said second insulation film with said movable electrode, wherein
- said movable electrode includes a first polysilicon layer having a compressive internal stress and a second polysilicon layer having a tensile internal stress, said first polysilicon layer and said second polysilicon layer being laminated in said thickness direction in a stated order from said fixed electrode, and
- said shield film is a fourth polysilicon layer having a compressive internal stress.
Dependencies are inferred from the claim text.