Integrated angular speed sensor device and production method thereof

• US 6,209,394 B1
• Filed: 10/23/1998
• Issued: 04/03/2001
• Est. Priority Date: 10/23/1997
• Status: Expired due to Term

• Current Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Original Assignee: STMicroelectronics SRL (STMicroelectronics NV)
• Inventors: Cuccia, Aurea, Montanini, Pietro, Ferrari, Paolo, Vigna, Benedetto, Ferrera, Marco
• Primary Examiner(s): Kwok, Helen C.
• Application Number:
  US09/178,285
• Time in Patent Office: 893 Days
• Field of Search: 73/504.12, 73/504.14, 73/504.15, 73/504.04, 73/504.16, 73/1.37, 73/514.32
• US Class Current: 73/504.14
• CPC Class Codes: G01C 19/574 the devices having two sensing masses in anti-phase motion
• CPC Class Codes: G01C 19/5769 Manufacturing; Mounting; Housings
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: H01L 21/76202 using a local oxidation of silicon, e.g. LOCOS, SWAMI, SILO H01L21/76235 takes precedence; together with vertical isolation, e.g. LOCOS in a SOI substrate, H01L21/76264
• CPC Class Codes: H01L 21/764 Air gaps H01L21/76264 takes precedence

Abstract

An angular speed sensor comprises a pair of mobile masses which are formed in an epitaxial layer and are anchored to one another and to the remainder of the device by anchorage elements. The mobile masses are symmetrical with one another, and have first mobile excitation electrodes which are intercalated with respective first fixed excitation electrodes and second mobile detection electrodes which are intercalated with second fixed detection electrodes. The first mobile and fixed excitation electrodes extend in a first direction and the second mobile and fixed detection electrodes extend in a second direction which is perpendicular to the first direction and is disposed on a single plane parallel to the surface of the device.

Claims

1. An integrated angular speed sensor device, comprising a mobile structure anchored to a semiconductor material body and having first mobile excitation electrodes which are intercalated with first fixed excitation electrodes, said first mobile and first fixed excitation electrodes having a first direction of extension, and second mobile detection electrodes which are intercalated with second fixed detection electrodes, said second mobile and second fixed detection electrodes having a second direction of extension which is substantially perpendicular to said first direction, wherein said mobile structure comprises a first and a second mobile mass of quadrangular shape, said first and second mobile masses being separated from one another by an anchorage region, each of the first and second mobile masses having a first side which faces said anchorage region, a second side which is parallel to said first side, and a third and a fourth side which are parallel to one another and perpendicular to said first and second sides;

the speed sensor device further comprising fixed first and second anchor sections positioned on opposite sides of the mobile structure; and

first and second spring elements attached to and extending between the anchor sections in the anchorage region, the first spring element being attached to the first side of the first mobile mass and the second spring element being attached to the first side of the second mobile mass.

2. A device according to claim 1 wherein said semiconductor material body has a surface in a plane, and wherein said first and said second directions are in the plane of the surface.

3. A device according to claim 1 wherein said first and second spring elements are parallel to and spaced apart from one another in the anchorage region.

4. A device according to claim 3 wherein each said spring element comprises a pair of first anchorage sections extending from a center portion of said first side of a respective one of said mobile masses and a pair of U-shaped second anchorage sections respectively connecting one of said first anchorage sections to a respective one of the first and second anchor sections.

5. A device according to claim 1, further comprising L-shaped anchorage elements extending from opposite corners of each mobile mass, each anchorage element having a first section extending parallel to said first direction and a second section extending parallel to said second direction.

6. A device according to claim 1 wherein said mobile excitation electrodes extend from said third and fourth sides of said mobile masses, and wherein said mobile detection electrodes extend from said second side of said mobile masses.

7. A device according to claim 6 wherein said fixed excitation electrodes comprise first fixed electrodes and second fixed electrodes arranged adjacent to one another and facing both said third and fourth sides of said mobile masses, said first fixed electrodes being biased to different voltages from said second fixed electrodes, said fixed excitation electrodes of said first mobile mass being biased with a voltage which alternates in counter-phase to said fixed excitation electrodes of said second mobile mass.

8. A device according to claim 7 wherein said first and second fixed electrodes and said fixed detection electrodes extend from respective fixed support regions, and are electrically separated from one another and from said mobile masses by a shaped trench, and wherein said fixed support regions are connected to respective buried contact regions which extend in a substrate region of said semiconductor material body.

9. A device according to any one of the preceding claims wherein said semiconductor material body comprises a monocrystalline substrate and a pseudo-epitaxial layer extending on said substrate and including a polycrystalline epitaxial region and a monocrystalline epitaxial region adjacent to one another, said mobile structure and said fixed excitation and detection electrodes being formed in said polycrystalline epitaxial region, and wherein the device includes signal processing electronic elements formed in said monocrystalline epitaxial region.

10. An integrated angular speed sensor device, comprising:

a semiconductor body having a surface in a plane;

a mobile structure anchored to the semiconductor body;

mobile excitation electrodes coupled to the mobile structure and to the semiconductor body;

fixed excitation electrodes alternating with said mobile excitation electrodes, said mobile and fixed excitation electrodes having a first direction of extension;

mobile detection electrodes coupled to the mobile structure and to the semiconductor body; and

fixed detection electrodes alternating with said mobile detection electrodes, said mobile and fixed detection electrodes having a second direction of extension at an angle to said first direction, the mobile and fixed excitation and detection electrodes all being in the plane of the surface;

wherein the semiconductor body includes a buried contact region that is doped to provide a conductive path, the buried contact region being electrically connected to the fixed electrodes.

11. The device of claim 10 wherein said mobile structure comprises:

a first mobile mass;

a second mobile mass, said first and second mobile masses formed adjacent to and spaced apart from one another; and

an anchorage region formed therebetween, each of the first and second mobile masses having a first side facing said anchorage region, said first and second mobile masses being each anchored to a bulk region of said semiconductor body through first and second anchorage elements extending on opposite sides of each of said first and second mobile masses.

12. The device of claim 11 wherein said first anchorage elements extend in said anchorage region and form a pair of fork elements, each fork element including:

a pair of first anchorage sections extending from a center portion of said first sides of said first and second mobile masses; and

a pair of U-shaped second anchorage sections having reciprocally facing concavities and a common section.

13. The device of claim 10 wherein said second anchorage elements extend from opposed points on each said mobile mass and are L-shaped, with a first section extending parallel to said first direction and a second section extending parallel to said second direction.

14. The device of claim 10 wherein said semiconductor body comprises a monocrystalline substrate and a pseudo-epitaxial layer extending on said substrate and including a polycrystalline epitaxial region and a monocrystalline epitaxial region adjacent to one another, said mobile structure and said fixed excitation and detection electrodes being formed in said polycrystalline epitaxial region, and wherein the device includes signal processing electronic elements formed in said monocrystalline epitaxial region.