不同衬底条件对MEMS压阻传感器性能的影响

Investigation of Piezoresistive MEMS Sensors with Different Substrates

为了研究不同衬底条件对MEMS压阻传感器性能的影响，采用3种掺杂条件的衬底进行实验测试．在各步骤热过程后，对3种衬底条件下压阻区、引出区和保护框的方块电阻进行了测量和分析．通过对各部分方块电阻的测量可以看出，对于压阻区（P^-区），A#和B#的方块电阻在开始注入扩散时相差很小，而由于注入杂质在高温下进一步扩散，衬底掺杂浓度对扩散后杂质分布的影响加大，方块电阻在后续的热过程中差别增大．通过比较不同衬底条件下各个热过程后的压阻数据，发现在3种掺杂条件中，20～40Ω·cm的衬底最符合预期压阻的设计．此结论已用于指导实际产品生产．

Three kinds of substrates were used to investigate the performance of piezoresistive MEMS sensors in this experiment.Sheet resistances of piezoresistive area, contact area and protecting area were tested and analysed after the high temperature steps.For piezoresistive areas （ P- area ） , there was no difference between the sheet resistances of A# and B# substrates at the beginning of ions implantation, however, differences became obvious gradually after the impurities diffusing under high temperature condition, because the dopant concentration of substrate had greater effect on impurity distribution after diffusing.By comparing the sheet resistances of piezoresistive areas, the substrate of 20-40 Ω·cm is the best for the design, which has already been used in production.