A strong nose for trouble

Ammonia gas – it is both highly poisonous and corrosive, yet also often used in industry, or present around intensive livestock farming. To better mitigate the risks of ammonia leaks, Paddy French together with Lina Sarro and Sten Vollebregt will make smaller, more robust and eventually more affordable ammonia sensors. The NWO OTP programme has funded their research into a fully-integrated, single-chip sensor that incorporates two porous silicon carbide structures for detecting ammonia and humidity, all in a single layer and one etch step.

Silicon carbide (SiC), known for its exceptional strength and durability, is the ideal material for a sensor chip in more demanding environments. For example, when measuring the presence of ammonia, which is highly corrosive. By combining this incredibly strong chip material with standard CMOS technology and a post-processing step, the SiC structures can be seamlessly integrated into the chip, resulting in a compact, cost-effective, and highly robust sensor device.

Compared to normal silicon, there are still many practical limitations to SiC chips. The research fund aims to support the deposition and porous structure development of the sensor chip, focusing on understanding and optimising the porous silicon carbide structures. By delving deeper into the intricacies of the porous structure and its formation process, researchers seek to refine the sensor's sensitivity and accuracy in detecting target substances.

The potential impact of this sensor chip extends beyond industrial and agricultural settings, with applications in transportation sectors like shipping, lorries and diesel trains, as well as in hydrogen production with electrolysers. The sensor's ability to detect ammonia and humidity levels accurately opens up possibilities for improved safety measures and environmental monitoring in various fields.

The sensor chip's development is a collaborative effort involving researchers, industry partners and potential end-users to tailor the technology to meet specific needs. The goal is to create a user-centric solution that not only enhances detection capabilities but also offers longevity and cost-efficiency compared to existing sensor technologies.