1. Field of the Invention
The present invention relates to a strain measuring device and a system that can measure strain.
2. Description of Related Art
So far, a semiconductor single crystalline substrate comprising local impurity diffused resistors is known as a mechanical quantity measuring device. As described in JP-A-2006-003182, there is a method to measure strain of an object by attaching this mechanical quantity measuring device to the object, based on change of the resistance of the impurity diffused resistors caused by the strain. In this method, four impurity diffused resistors through which current can flow in a specific direction are used to form a Wheatstone bridged circuit (hereafter, referred to as a bridged circuit) so as to measure strain in a specific direction of the substrate by utilizing anisotropy of the crystal orientation in strain sensitivity of the impurity diffused resistor. Furthermore, as described in FIG. 18 of JP-A-2006-003182, it is also proposed that each impurity diffused resistor is configured to a meander shaped strip line by being connected plural strip lines by a contact and/or a wiring in order to reduce power consumption of the mechanical quantity measuring device.
In the above related art, however, there is a possibility of decreasing measurement accuracy due to offset or fluctuation of sensitivity resulting from the variability of sheet resistance of p-type impurity diffused resistors in especial.