CMOSMEMS

CMOSMEMS refers to the integration of micro-electromechanical systems devices with complementary metal-oxide-semiconductor circuitry on a common silicon substrate or within a single package. The term covers both monolithic integration where MEMS structures and CMOS electronics share fabrication steps, and heterogeneous approaches where MEMS devices are bonded to CMOS layers or stacked above them. The aim is to enable sensing, actuation, and signal processing with minimal interconnect length and power consumption, producing compact, cost-effective silicon microsystems.

Fabrication approaches include post-CMOS MEMS processing, surface or bulk micromachining performed after CMOS circuitry, and MEMS-on-CMOS techniques where the MEMS layer is formed in proximity to intact electronics. Alternatively, wafer bonding and through-silicon vias can integrate MEMS with pre-fabricated CMOS. Materials are typically silicon-based, using polysilicon or single-crystal silicon for movable structures, with oxides or metals for electrodes and coatings. Packaging often requires hermetic sealing of MEMS cavities while protecting the electronics from contaminants and moisture.

Devices realized in CMOSMEMS span inertial sensors such as accelerometers and gyroscopes, pressure sensors, microphones, and RF MEMS switches and resonators. On-chip electronics enable amplification, analog-to-digital conversion, calibration, and digital control, improving performance and reducing external components. Applications include mobile devices, automotive safety systems, industrial sensing, medical devices, and Internet of Things sensors.

Advantages include reduced parasitic losses, smaller form factors, lower assembly costs, and the potential for true system-on-a-chip integration. Challenges involve process compatibility between MEMS and CMOS, reliability and long-term stability of MEMS structures, packaging constraints, thermal effects, and yield management. Ongoing research focuses on improving fabrication techniques, packaging methods, and design methodologies to maximize performance and scalability.