Australia has taken the lead in producing SiC sensors

Griffith University’s Queensland Micro and Nanotechnology Centre (QMNC) is combining high-quality silicon carbide (SiC) nanofilms with MEMS devices to produce robust sensors for harsh environments.

The world-leading quality of the Centre’s SiC layers has revealed material properties that can be used in a new generation of miniature sensors. Once incorporated into MEMS-based devices, a plethora of applications open up.

Their single crystal, nanometre-thin films can be applied to silicon wafers that are 300mm in diameter, and feature an ultra-smooth surface roughness of less than 0.5nm. The films were grown using ANFF Q’s low-pressure chemical vapor deposition (LPCVD) reactor at 1,000 °C.

The SiC samples have demonstrated a piezoresistive characteristic that provides 15 times more sensitivity to mechanical stresses than metals. They remain sensitive at 400ºC, making them ideal for sensing applications in harsh environments.

“With the platform technology for batch fabrication of SiC-MEMS/NEMS transducers, we can produce tens of thousands of micro sensors on a single SiC-on-Si wafer,” Professor Nam-Trung Nguyen, a researcher at QMNC and Deputy Director of ANFF-Q, said.

“This high throughput will significantly reduce the total cost of the sensors and is relevant to a wide range of applications. Especially sensing in harsh environments, such as those in mining, automotive, defence, and power industries, this will allow a quick penetration into the commercial market,” he continued.

QMNC is the only research centre in Australia with the capability of growing high-quality SiC nanometre-thin films, but the researchers there have maximised their outcomes through numerous inter-institutional collaborations. This includes work with UQ on SiC-on-glass waferbonding, with University of Tokyo on SiC piezoresistive effects, and with Stanford University on bulk SiC-based sensing devices.

The work has been largely conducted at ANFF-Q using equipment for microprocessing that ranged from chromium mask production at UQ to SiC-on-Si growth and SiC micro-machining at Griffith.

“The support from ANFF and our industrial partner SPT in establishing world-class micro/nanofabrication facilities in the Queensland node was an important factor, which led to the success of this project,” Nam-Trung said.