Early stage fault detection in fabrication process

1 min read

A tool that is able to spot defects or unwanted features much earlier in the fabrication process in everyday technology such as mobile phones and batteries, has been created by a team from the Australian National University (ANU).

The device works by capturing high-resolution images of semiconductor materials, including many potential defects, within seconds, according to lead author Dr Hieu Nguyen from the ANU Research School of Electrical, Energy and Materials Engineering.

"We're calling it 'the miracle of speed and space'. It's not just several times faster than techniques currently being used - it's tens of thousands of times faster," said Dr. Nguyen.

"This opens the door to a new generation of ultra-high resolution, precise characterisation and defect-detection tools for both research and industry sectors."

The ANU researchers, in collaboration with scientists from the National Renewable Energy Laboratory in the US, discovered the light emitted from various semiconductor materials, including silicon, perovskites and many thin films, had some very distinct qualities.

Once this light is captured on camera, the optical images can be used to gather important information about how the material works.

"Now we know much more about the property of the light - and, just from the image, we can extract different information with incredible depth," Dr. Nguyen added.

"The beautiful part of this research is that we used ordinary tools that are commercially available, and converted them into something extraordinary."

The team demonstrated their method by capturing images of the optical bandgap, one of the first pieces of information researchers need to know about a material. This bandgap determines many properties of semiconductors, including the ability to absorb light and conduct electricity.

"We tested this invention extensively on various state-of-the-art perovskite solar cells made here at ANU and independently confirmed the results with many other low-speed or low-resolution techniques. They matched perfectly," Dr. Nguyen said.

"We are refining the invention so that it can be commercialised."

"Before this invention, it took an entire week to get a high-quality bandgap image on a device. Now, with our invention, it takes just a few seconds to get an image with the same quality," noted co-author Boyi Chen from ANU.

"This invention will help to produce more robust mobile phones, solar cells, sensors and other optical devices as it can spot defects very early in the fabrication process."