MEMS Based Si Strain Gauge With Arc-Shaped Piezoresistors

초록

The Si strain gauge is a commonly utilized component in the construction of diaphragm-type high-pressure sensors. However, in specific applications, these sensors may encounter reduced output sensitivity due to limitations in their mounting positions. To address this issue, a novel half-bridge silicon strain gauge was developed using Silicon-on- Glass (SiOG) substrate technology. This innovative design consists of two components: an arc gauge that measures tangential strain and a linear gauge that gauges radial strain. The tangential gauge features grid patterns, including reciprocating arcs of silicon piezoresistors on a thin glass substrate. By connecting two of these half-bridges to create a full bridge with arc-shaped gauges sensitive to tangential strain, a significant increase in output sensitivity is achieved compared to traditional half- bridge setups. Pressure sensors were subjected to testing across a range of pressures from 0 to 50 bar at five different temperatures. The results indicate a linear output with a typical sensitivity of approximately 16 mV/V/bar, a maximum zero shift of 0.05% Full Scale (FS), and a span shift of 0.03% FS. The enhanced output capabilities of these pressure sensing gauges yield stronger signals, thereby maintaining a superior signal-to-noise ratio when compared to conventional pressure sensors.