Kubos Semiconductors from the UK and the UK Compound Semiconductor Centre (CSC) announced that their partnership to commercialize cubic GaN epitaxy for the manufacture of high efficiency green and amber LEDs.
Hexagonal GaN crystals have been widely used to fabricate blue LEDs, but achieving efficient operation in green devices is a problem. Large polarization fields in the active regions of these longer-wavelength structures reduce radiative recombination rates and limit LED efficiency.
Targeting the issue, Kubos Semiconductors develops process based on growing cubic GaN on 3C (cubic) SiC on silicon substrates. Unlike hexagonal GaN, cubic GaN is electric-field free, removing polarization issues and opening the door to the design of efficient LEDs.
(Image: Kubos Semiconductors)
The epitaxy process for 3C SiC on silicon was pioneered by Warwick University spin-out, Anvil Semiconductors. Anvil then started to grow 3C SiC on silicon wafers for SiC Power devices, overcoming the associated mismatches in the different materials’ lattice parameters and thermal expansion coefficients. The company then partnered with Cambridge University to grow cubic GaN on the cubic SiC on Si templates, achieving the world’s first 150 mm wafer with 100% cubic GaN grown on it.
The recent Kubos-CSC partnership is set to accelerate Kubos’ technical development. CSC provides commercial access to industry standard epitaxy tools, providing clear routes to commercialization.
Key applications include Micro LEDs for display markets as well as automotive and conventional LED lighting markets. Kubos and partners are thus working on raising the efficiencies of the green LEDs that will be fabricated via its process.
