The effects of poly-SiGe on sensing properties for ultra-low-power CMOS-embedded MEMS sensors

To compare Si and poly-SiGe as MEMS structural materials having 20 pm-thick, we fabricated a capacitive accelerometer on an 8-inch Si substrate using CMOS standard process and measured capacitance sensitivities of an identical sensor design. As a result, we found that the sensitivity of the SiGe sensor is 2.1 times larger than that of the Si sensor. We also confirmed that the SiGe sensor can attain lower noise level as well as lower power consumption, thanks to the higher mass density of SiGe and availability of CMOS-embedded SiGe MEMS structure. The results indicate that the poly-SiGe film is promising candidates for future CMOS-embedded sensor technology applications.