MEMS (Micro Electro Mechanical System) piezoresistive type absolute pressure sensor based on SOI (Silicon on Insulator) silicon chip

Abstract

The invention provides an MEMS (Micro Electro Mechanical System) piezoresistive type absolute pressure sensor based on an SOI (Silicon on Insulator) silicon chip, which comprises a substrate provided with a quadrilateral slot and four groups of piezoresistors manufactured on the side wall of the slot, wherein the four groups of piezoresistors form a Wheatstone bridge; the two opposite side walls of the quadrilateral slot are arranged along a crystal orientation (100) of the substrate, and the other opposite side walls of the quadrilateral slot are arranged along a crystal orientation (101) of the substrate. The MEMS piezoresistive type absolute pressure sensor comprises the following manufacturing steps: photoetching and defining a P type heavily-doped lead contact area on the front surface of the substrate for ion implantation and high-temperature thermal annealing; photoetching and defining the shape of the slot on the front surface of the substrate and etching the quadrilateral slot; doping the piezoresistors on the side walls through P type ion implantation light doping and carrying out high-temperature thermal annealing; manufacturing a lead hole and a metal lead; and scribing. The MEMS piezoresistive type absolute pressure sensor has the beneficial effects that no strain film is contained, the chip size of the sensor can be reduced, the anti-overload capacity of the sensor is remarkably increased, and the process reliability and the device yield are improved.

Description

technical field [0001] The invention belongs to the field of micro-electro-mechanical system (MEMS) sensor design, and relates to a MEMS piezoresistive absolute pressure sensor and a method for manufacturing the pressure sensor on a single wafer using a MEMS processing technology. Background technique [0002] MEMS (Micro Electro Mechanical System) is an emerging interdisciplinary high-tech research field. The piezoresistive pressure sensor based on MEMS technology has been widely used in the modern market due to its excellent accuracy and reliability and relatively cheap manufacturing cost. Silicon-based piezoresistive pressure sensors have been widely used since the discovery of the piezoresistive properties of silicon materials in the mid-1950s. The working principle of a typical piezoresistive pressure sensor is to make four pressure-sensitive resistors in the stress concentration area by diffusion or ion implantation on a square or circular silicon strained film, and t...

AI Technical Summary

Problems solved by technology

Due to the existence of the strain film, limited by the fracture strength of the silicon material, the traditional piezoresistive pressure sensor has limited anti-overload ability, and the piezoresistive pressure sensor in the application field of high pressure has the disadvantage of low anti-overload ability.

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