Highly Sensitive ZnO MEMS Sensor Fabrication with Atomic Layer Deposition Technique

Abstract

To obtain integrated and miniaturized gas sensors with low cost and power consumption to meet the increasing request of the internet of things industry and other relative areas, this work presented an in-situ compatible manufacturing and high-throughout strategy to deposit gas sensing film on a 5-inch wafer integrated with more than 10,000 MEMS micro-hotplates (MHP). The-state-of-art atomic layer deposition (ALD) was employed to fabricate controllably the uniform ZnO thin film (20 nm) on Micro-Electro-Mechanical Systems (MEMS) chips for constructing gas sensors. The ALD ZnO based MEMS sensors display excellent sensing performance, including very high sensitivity and selectivity to H2S with a limit of detection (LOD) on ppb level, good stability and quick response and recover dynamics under 70 mW of power dissipation. The sensing film has higher to 1300 times in mechanical strength than the traditional film from drop-coating. Furthermore, The ALD technique offers a facile in-situ strategy and high-throughput fabrication of MEMS gas sensors.