Porotech raises £3m for microdisplay development

Cambridge University spin-out Porotech has raised £3m to fund the development of its micro-LED production technique that promises a new era of brighter and sharper microdisplays.

Micro-LED is the next evolutionary stage for displays on products including smartphones, smartwatches and VR/AR headsets. It is particularly useful outdoors where sunlight can make existing displays difficult to see but the performance of current micro-LEDs deteriorates as device sizes shrink.

According to Porotech, their new class of porous gallium nitride (GaN) semiconductor material offers performance improvements suitable for mass production or customisation and in November 2020 the company launched what it said was the world’s first commercial native red indium gallium nitride (InGaN) LED epiwafer for micro-LED applications.

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Porotech’s next step is to expand its novel approach to integrate InGaN-based red, green, and blue (RGB) micro-LEDs for full-colour microdisplays, leading to the creation of 'smart' pixels that can be controlled independently for exceptional responsiveness and accuracy in applications such as AR gesture.

Currently, technologies being tested for smart pixels are largely based on aluminium indium gallium phosphide (AlInGaP) material and quantum dot colour conversion (QDCC). AllnGaP is said to struggle at the small pixel sizes required by AR, and QDCC suffers from uniformity and stability issues. Both approaches require a mixture of different material.

Porotech's novel approach reportedly enables all three primary colours to be made with the same GaN material and integrated on a single wafer without the need for special structuring.

"Porous GaN is basically GaN with tiny holes in it that are a few tens of nanometres across," Porotech CEO and co-founder Dr Tongtong Zhu said in a statement. "It's an entirely new engineered GaN material platform to build semiconductor devices on. It offers performance improvements that are suitable for mass production, scalable in wafer size – and crucial for the next generation of microdisplay devices such as AR glasses.”

"We are already seeing high levels of demand for our standard and customised porous GaN substrates and micro-LED epiwafers, which we can provide on sapphire and silicon platforms ranging from 100mm to 300mm” Dr Zhu added. “Smart pixels will be our next development – monolithically generated and integrating native self-emissive RGB micro-LEDs on a single wafer to give smaller, lighter, thinner displays that use less energy and offer the greater accuracy required for things like AR gestures."

Porotech's latest funding round was led by Speedinvest, with participation from previous investors IQ Capital, Cambridge Enterprise, Martlet, and Cambridge Angels.