MEMS高温压力传感器耐高温引线结构优化

绝缘体上硅(SOI)高温压力传感器可在高温(高于125 ℃)下工作。通常情况下构成惠斯通电桥的电阻单独处于压力敏感区,以提高其灵敏度,但在其工作期间压力传感器器件区电阻重掺区与金属引线连接处存在一定高度差,在加压加电高温环境下此处热应力变大,金属引线因过热而出现金属引线断裂或失效,无法满足高温需求。在此基础上研究了一种硅引线技术,使其与压敏电阻处于同一高度层,金属引线平铺在硅引线上端,经退火后形成良好的欧姆接触。实验测试表明,该方案能使压力传感器在300 ℃高温环境下正常工作,金属引线与电阻区连接完好,传感器敏感区应力降低接近50%,且优化后传感器灵敏度符合设计要求。

Optimization of High-Temperature-Resistant Lead Structure for MEMS High-Temperature Pressure Sensors

Silicon-on-insulator high-temperature pressure sensors can operate at temperatures above 125 °C due

to their unique properties.Generally, the resistance forming the Wheatstone bridge is located solely in the pressuresensitive

region to enhance its sensitivity.However, during its operation, a certain height difference exists between

the resistance of the heavily doped region of the pressure sensor device and its connection with the metal lead.The

thermal stress in this area increases under high-temperature conditions during pressurization and electrification.Metal

leads cannot meet the high-temperature requirements and may break or fail due to overheating.Therefore, this

study investigated a silicon lead technology that had the same layer height as a varistor.A metal lead was laid flat on

this silicon lead, and the end was annealed to form a robust ohmic contact.Experimental testing demonstrated that

this method could ensure the normal operation of the pressure sensor in a high-temperature environment of 300 °C.

The metal lead was well connected to the resistance zone.The stress in the sensitive area of the sensor was reduced

by nearly 50%, and the optimized sensor sensitivity met the design requirements