Measurement method of piezoresistive coefficient of double-end fixed beam based on soi silicon chip

Abstract

The invention discloses a method for measuring the piezoresistive coefficient of a double-end fixed-supported beam based on SOI silicon wafers, which includes the following steps: through force analysis, it is obtained that under the action of an electrostatic force uniform load, the upper part of the double-ended fixed-supported beam is located at The size of the compressed area in the middle position is the length of the double-end fixed beam, and it is doped within this range; the two ends of the doped area are heavily doped; in the heavily doped area, the corresponding anchor Metal aluminum is deposited in the region and the region between the heavily doped region and the anchor region; multiple metal wires are connected on the anchor region; a semiconductor parameter tester capable of measuring resistance is connected between the metal wires in the two anchor regions; An external voltage source that can apply an electrostatic bias voltage is added between the metal wire in the anchor area and the electrode of the substrate; the piezoresistive coefficient of the double-terminal anchored beam is measured and calculated. The invention avoids the canceling effect of the tension region and the compression region in the double-end fixed support beam, and has accurate measurement results and simple and convenient measurement method.

Description

technical field [0001] The invention relates to a method for measuring the piezoresistive coefficient, in particular to a method for measuring the piezoresistive coefficient of a double-end fixed-supported beam based on SOI silicon chips. Background technique [0002] see figure 1 , the SOI silicon wafer includes substrate 1, left and right supports 2, and double-end fixed support beams 3 from bottom to top. Both the substrate 1 and the double-ended support beams 3 are silicon layers, and the left and right supports 2 are silicon dioxide layers. . [0003] When the size of the double-end fixed-supported beam 3 is reduced to the nanometer level, its mass is greatly reduced, resulting in a resonant frequency up to GHz, a quality factor, a greatly improved sensitivity, and a significantly reduced power consumption. These characteristics make the double-end fixed-support beam 3 have good application prospects in resonators, filters, biochemical sensors, and the like. With the...

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Problems solved by technology

In the process of measuring the piezoresistive coefficient by using the atomic force microscope probe to apply a load to the double-end fixed beam 3, we found that for the double-end fixed beam 3, the anchor regions near both ends are in tension, and the middle part is in compression. In this way, the resistance changes caused by the piezoresistive effect in the tension area and compression area of ​​the double-end fixed beam cancel each other out, which greatly reduces the measurement accuracy.

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