Stress sensing devices and methods

A method of sensing stress in a sensor device comprising:

• inducing a current to flow in an active layer in at least two operating modes, the current having a horizontal component and a vertical component with respect to a die surface;
• measuring a first resistance between two of at least three contacts coupled in a first configuration of a first operating mode, the first resistance related to a ratio of the horizontal and vertical components;
• measuring a second resistance between two of at least three contacts coupled in a second configuration of a second operating mode, the second configuration different from the first configuration, and the second resistance related to a ratio of the horizontal and vertical components;
• determining a ratio of the first resistance and the second resistance;
• and
• determining a mechanical stress acting on a device based on the ratio.

A method of sensing stress comprising:

• coupling a first sensor device and a second sensor device arranged perpendicularly to one another on a semiconductor wafer;
• inducing a current to flow in an active layer of the first and second sensor devices in a first operating mode, the current having a horizontal component and a vertical component in each of the first and second sensor devices, respectively, with respect to a die surface;
• measuring a first resistance between two of at least three contacts of the first and second sensor devices coupled in a first operating mode configuration, the first resistance related to a ratio of the horizontal and vertical components in the active layers of the first and second sensor devices;
• inducing a current to flow in an active layer of the first and second sensor devices in a second operating mode, the current having a horizontal component and a vertical component in each of the first and second sensor devices, respectively, with respect to a die surface;
• measuring a second resistance between two of at least three contacts of the first and second sensor devices coupled in a second operating mode configuration, the second resistance related to a ratio of the horizontal and vertical components in the active layers of the first and second sensor devices;
• determining a ratio of the first resistance and the second resistance;
• and
• determining a mechanical stress based on the ratio.

A circuit comprising:

• an active volume;
• at least three contacts spaced apart from one another in the active volume, the at least three contacts being coupleable in a first configuration for a first operating mode in which a current in the active volume has a first ratio of horizontal to vertical components with respect to a die surface and in a second configuration different from the first for a second operating mode in which a current in the active layer has a second ratio of horizontal to vertical components, the first and second ratios related to at least one boundary condition at the at least three contacts, wherein a ratio of a resistance between at least two of the contacts in the first operating mode and a resistance between at least two of the contacts in the second operating mode is related to mechanical stress in the sensor device;
• and
• a memory configured to store a reference ratio for comparison with the ratio of a resistance between at least two of the contacts in the first operating mode and a resistance between at least two of the contacts in the second operating mode.