Resistive element

Patent metadata

Field	Value
Publication number	US-9322840-B2
Application number	US-201313932718-A
Country	US
Kind code	B2
Filing date	Jul 1, 2013
Priority date	Jul 1, 2013
Publication date	Apr 26, 2016
Grant date	Apr 26, 2016

Abstract

A resistive element includes a resistive region in a semiconductor substrate, a first contact structure and a second contact structure. The semiconductor substrate includes a first main surface area. The resistive region extends in a lateral direction parallel to the main surface area and in a vertical direction perpendicular to the main surface area, and includes a first piezo-resistive coefficient for a current flow in the lateral direction and a second piezo-resistive coefficient for a current flow in the vertical direction. The first contact structure contacts a portion of a first face of the resistive region and the second contact structure contacts a portion of a second face of the resistive region. The resistive element generates a current flow distribution within the resistive region having a lateral component and a vertical component that results in a piezo-resistive coefficient of the resistive element.

First claim

The invention claimed is:

1. A resistive element having a specific piezo-resistive coefficient, wherein the resistive element comprises:
a resistive region of a single conductivity type formed in a semiconductor substrate, wherein the semiconductor substrate comprises a first main surface area, wherein the resistive region extends in a lateral direction parallel to the main surface area and in a vertical direction perpendicular to the main surface area, wherein the resistive region is isolated from the semiconductor substrate in the lateral direction and comprises for a stress component a first piezo-resistive coefficient for a current flow in the lateral direction and a second piezo-resistive coefficient, different from the first piezo-resistive coefficient, for a current flow in the vertical direction;
a first contact structure arranged to contact at least a portion of a first face of the resistive region parallel to the main surface area and positioned at a first distance to the main surface area;
a second contact structure arranged to contact at least a portion of a second face of the resistive region different from the first face, parallel to the main surface area and positioned at a second distance to the main surface area different from the first distance;
wherein the resistive element is configured to generate, in response to an input signal applied to at least one of the first contact structure and the second contact structure, a current flow distribution within the resistive region between the first contact structure and the second contact structure, the current flow distribution having a lateral component and a vertical component;
wherein a combination of the lateral component and the vertical component results in a piezo-resistive coefficient of the resistive element which is defined by the ratio between the lateral component in the lateral direction in the resistive region having the first piezo-resistive coefficient for the current flow in the lateral direction and the vertical component in the vertical direction in the resistive region having the second piezo-resistive coefficient for the current flow in the vertical direction;
wherein the resistive element is configured such that a ratio between the lateral component and the vertical component is obtained within the resistive region which results in the specific piezo-resistive coefficient.

2. The resistive element according to claim 1 , wherein the first contact structure is formed such that the ratio between the lateral component and the vertical component is obtained within the resistive region which results in the specific piezo-resistive coefficient.

3. The resistive element according to claim 2 , wherein the first contact structure is configured to contact the first face of the resistive region in at least two different areas that are spaced apart from each other.

4. The resistive element according to claim 2 , wherein the first contact structure and the second contact structure are configured to contact at least 75% of the sum of the first face and the second face of the resistive region.

5. The resistive element according to claim 1 , wherein the resistive region comprises a confinement structure formed such that the ratio between the lateral component and the vertical component is obtained within the resistive region which results in the specific piezo-resistive coefficient.

6. The resistive element according to claim 5 , wherein the confinement structure is formed such that the resistive region comprises in a subarea a cross-section reduction in the lateral direction.

7. The resistive element according to claim 1 , wherein the resistive region is isolated in the lateral direction from the semiconductor substrate by an isolation structure, wherein the isolation structure is configured to provide a depletion region adjacent to at least one lateral face of the resistive region, wherein a width of the depletion region in the lateral direction is controllable to adjust the ratio between the lateral component and the vertical component in the resistive region.

8. The resistive element according to claim 7 , wherein the width of the depletion region is controllable by a reverse voltage applied to the depletion region.

9. The resistive element according to claim 1 , wherein the second contact structure is a single semi conductive region arranged to contact the second face of the resistive region, wherein a conductivity of the single semi conductive region is at least a factor of ten higher than a conductivity of the resistive region.

10. The resistive element according to claim 9 , wherein the single semi conductive region is buried in the semiconductor substrate such that it comprises neither the first main surface area of the semiconductor substrate or a second main surface area of the semiconductor substrate, opposing the first main surface area.

11. The resistive element according to claim 1 , wherein the specific piezo-resistive coefficient comprises a value that is between +3*10^(−10)/Pa and +6*10^(−10)/Pa times the sum of in-plane stress components parallel to the main surface area.

12. The resistive element according to claim 1 , wherein the resistive region comprises n-doped monocrystalline (100)-silicon having a doping concentration between 10^15/cm 3 and 10^18/cm 3 .

13. A method for generating a mechanical stress dependent signal with a resistive element, wherein the mechanical stress dependent signal comprises a specific mechanical stress dependency which is defined a specific piezo-resistive coefficient of the resistive element, wherein the resistive element comprises a resistive region formed in a semiconductor substrate, a first contact structure and a second contact structure, wherein the semiconductor substrate comprises a first main surface area, wherein the resistive region extends in a lateral direction parallel to the main surface area and in a vertical direction perpendicular to the main surface area, and wherein the resistive region is isolated from the semiconductor substrate in the lateral direction and comprises for a stress component a first piezo-resistive coefficient for a current flow in the lateral direction and a second piezo-resistive coefficient, different from the first piezo-resistive coefficient, for a current flow in the vertical direction, wherein the first contact structure is arranged to contact at least a portion of a first face of the resistive region parallel to the main surface area, wherein the second contact structure is arranged to contact at least a portion of a second face of the resistive region different from the first face and parallel to the main surface area, wherein the method comprises:
applying an input signal to at least one of the first contact structure and the second contact structure in order to generate a current flow distribution within the resistive region between the first contact structure and the second contact structure having a lateral component and a vertical component, wherein a combination of the lateral component and the vertical component results in a piezo-resistive coefficient which is defined by the ratio between the lateral component in the lateral direction in the resistive region having the first piezo-resistive coefficient for the current flow in the lateral direction and the vertical component in the vertical direction in the resistive region having the second piezo-resistive coefficient for the current flow in the vertical direction; and
wherein the resistive element is configured such that a ratio between the lateral component and the vertical component is obtained within the resistive region which results in the speci

Assignees

• Infineon Technologies Ag

Inventors

• Ausserlechner Udo

Classifications

• G01R33/07 Primary

  Hall effect devices · CPC title

• G01P15/123 Primary

  by piezo-resistive elements, e.g. semiconductor strain gauges · CPC title

• G01R33/0052

  Manufacturing aspects; Manufacturing of single devices, i.e. of semiconductor magnetic sensor chips (devices based on galvano-magnetic effect or the like H10N50/85) · CPC title