Piezoresistive pressure sensor with dual-unit configuration for on-chip self-compensation and suppression of temperature drift

Abstract

With our developed MIS (Microholes Inter-etch & Sealing) micromachining process that is implemented only from the front-side of single-side polished (111) silicon wafers, a novel piezoresistive pressure sensing unit and another identically structured pressure-insensitive dummy unit are on-chip integrated compactly to eliminate unbalance factors induced temperature-drift by mutual compensation between the two units. In addition, the two units are both suspended from silicon substrate to suppress the packaging-stress. The high-performance pressure sensors are low-cost fabricated in a single (111)-wafer by repeatedly using the single-sided MIS process. The tested ultra-low TCO (temperature coefficient of offset) of 0.002%/°C·FS (-40°C to +125°C) well verifies the highly stable performance of the developed sensor structure.