Stress compensated oscillator circuitry and integrated circuit using the same

Patent metadata

Field	Value
Publication number	US-9960733-B2
Application number	US-201615227262-A
Country	US
Kind code	B2
Filing date	Aug 3, 2016
Priority date	Feb 13, 2015
Publication date	May 1, 2018
Grant date	May 1, 2018

Abstract

A stress compensated oscillator circuitry comprises a sensor arrangement for providing a sensor output signal S Sensor , wherein the sensor output signal S Sensor is based on an instantaneous stress or strain component σ in the semiconductor substrate, a processing arrangement for processing the sensor output signal S Sensor and providing a control signal S Control depending on the instantaneous stress or strain component σ in the semiconductor substrate, and an oscillator arrangement for providing an oscillator output signal S osc having an oscillator frequency f osc based on the control signal S Control , wherein the control signal S Control controls the oscillator output signal S osc , and wherein the control signal S Control reduces the influence of the instantaneous stress or strain component σ in the semiconductor substrate onto the oscillator output signal S osc , so that the oscillator circuitry provides a stress compensated oscillator output signal.

First claim

The invention claimed is:

1. Stress compensated oscillator circuitry, comprising:
a sensor arrangement for providing a sensor output signal, the sensor arrangement comprising a stress-sensitive sensor element and a stress-insensitive resistive element, wherein the sensor output signal is based on an instantaneous stress or strain component in a semiconductor substrate,
a processing arrangement for processing the sensor output signal and providing a control signal depending on the instantaneous stress or strain component in the semiconductor substrate, and
an oscillator arrangement for providing an oscillator output signal having an oscillator frequency based on the control signal,
wherein the stress-sensitive sensor element provides a stress dependent sensor signal having a stress component dependency with respect to at least one of a sum of normal stress components, a difference of the normal stress components, or a shear stress component in the semiconductor substrate, wherein the stress-insensitive resistive element provides a stress-insensitive signal, and wherein the sensor output signal is based on a combination of the stress dependent sensor signal and the stress-insensitive signal; and
wherein the control signal controls the oscillator output signal, and wherein the control signal reduces an influence of the instantaneous stress or strain component in the semiconductor substrate onto the oscillator output signal, so that the stress compensated oscillator circuitry provides a stress compensated oscillator output signal.

2. The stress compensated oscillator circuitry according to claim 1 , wherein the stress-sensitive sensor element comprises a piezo-sensitive sensor element, and wherein the stress-insensitive resistive element comprises a Poly-Si resistive element or a metal resistive element.

3. The stress compensated oscillator circuitry according to claim 2 , wherein the stress-insensitive resistive element has a low stress coefficient, with ΔR(σ)<5 or 2%/GPa.

4. The stress compensated oscillator circuitry according to claim 1 , wherein the sensor output signal is based on a comparison of the stress dependent sensor signal and the stress-insensitive signal.

5. The stress compensated oscillator circuitry according to claim 1 , wherein the sensor arrangement, the processing arrangement, and the oscillator arrangement are integrated on a same semiconductor substrate.

6. The stress compensated oscillator circuitry according to claim 1 , wherein the sensor arrangement comprises a plurality of stress-sensitive sensor elements, each of the plurality of stress-sensitive sensor elements sensing the instantaneous stress or strain component in the semiconductor substrate.

7. The stress compensated oscillator circuitry according to claim 6 , wherein the plurality of stress-sensitive sensor elements are configured to sense the instantaneous stress and strain components which are orthogonal to each other and in plane with respect to a surface of the semiconductor substrate.

8. The stress compensated oscillator circuitry according to claim 6 , wherein the plurality of stress-sensitive sensor elements are piezo-sensitive sensor elements.

9. The stress compensated oscillator circuitry according to claim 8 , wherein the plurality of stress-sensitive sensor elements comprises lateral piezo-sensitive sensor elements which extend lateral in the semiconductor substrate with respect to a surface of the semiconductor substrate and further comprises vertical piezo-sensitive sensor elements, which extend vertical in the semiconductor substrate with respect to the surface of the semiconductor substrate.

10. The stress compensated oscillator circuitry according to claim 9 , wherein the lateral piezo-sensitive sensor elements are L-shaped sensor elements and are spatially distributed across the surface of the semiconductor substrate.

11. The stress compensated oscillator circuitry according to claim 10 , wherein the L-shaped sensor elements are piezo-sensitive diffusion resistors.

12. The stress compensated oscillator circuitry according to claim 8 , wherein the piezo-sensitive sensor elements comprises a first number of piezo-sensitive sensor elements having a first stress coefficient and comprises a second number of piezo-sensitive sensor elements having a second stress coefficient, wherein the first and second stress coefficients are different.

13. The stress compensated oscillator circuitry according to claim 12 , wherein the first number of piezo-sensitive sensor elements provides a first stress dependent sensor signal having a first stress component dependency and the second number of piezo-sensitive sensor elements providing a second stress dependent sensor signal having a second stress component dependency, wherein the first stress dependent sensor signal has a stress component dependency with respect to the sum of the normal stress components in the semiconductor substrate, and wherein the second number of piezo-sensitive sensor elements provide the second stress dependent sensor signal with a stress component dependency with respect to the difference of the normal stress components in the semiconductor substrate.

14. The stress compensated oscillator circuitry according to claim 1 , wherein the sensor arrangement further comprises a temperature sensor element on or in the semiconductor substrate for providing a temperature sensor signal with respect to an instantaneous temperature of the semiconductor substrate.

15. The stress compensated oscillator circuitry according to claim 14 , wherein the sensor arrangement comprises a plurality of temperature sensor elements which are spatially distributed over a surface of the semiconductor substrate.

16. The stress compensated oscillator circuitry according to claim 15 , wherein the plurality of temperature sensor elements form a differential temperature sensor arrangement.

17. The stress compensated oscillator circuitry according to claim 1 , wherein the processing arrangement is configured to perform a feed-forward sensor output signal processing for providing the control signal as a stress compensation signal to the oscillator arrangement.

18. The stress compensated oscillator circuitry according to claim 17 , wherein the processing arrangement is configured to use a look-up table or to calculate a polynomial function or piece-wise linear function based on the sensor output signal in order to determine the control signal.

19. The stress compensated oscillator circuitry according to claim 1 , wherein the processing arrangement is configured to process the sensor output signal in order to provide the control signal which is a combination of a plurality of partial control signals, wherein each of the plurality of partial control signals controls the oscillator frequency of the oscillator output signal and reduces an influence of a different instantaneous component in the semiconductor substrate onto the oscillator frequency of the oscillator output signal.

20. The stress compensated oscillator circuitry according to claim 1 , wherein the processing arrangement is configured to process the sensor output signal in order to provide the control signal, wherein the control signal comprises a first partial control signal and a second partial control signal to provide a first partial correction signal and a second partial correction signal for different stress component dependencies of the oscillator arrangement in the semiconductor substrate.

21. The stress compensated oscillator circu

Assignees

• Infineon Technologies Ag

Inventors

• Motz Mario

Classifications

• H03B5/24

  active element in amplifier being semiconductor device (H03B5/26 takes precedence) · CPC title

• H03L1/026

  by using a memory for digitally storing correction values (H03L1/025 takes precedence) · CPC title

• G01L1/18

  using properties of piezo-resistive materials, i.e. materials of which the ohmic resistance varies according to changes in magnitude or direction of force applied to the material · CPC title

• H03L7/00

  Automatic control of frequency or phase; Synchronisation · CPC title

• H03L1/027

  by using frequency conversion means which is variable with temperature, e.g. mixer, frequency divider, pulse add/subtract logic circuit (H03L1/023, H03L1/026 take precedence) · CPC title