Plessey, an embedded technologies developer at the forefront of microLED technology for the augmented reality (AR) and display markets, have successfully developed a world’s first GaN on Silicon-based Red LED.
Whilst InGaN-based Blue and Green LEDs are commercially available, Red LEDs are typically based on AlInGaP material or colour converted Red. For AR, achieving high efficiency ultra-fine pitch Red pixels (< 5 µm) remains elusive due to severe edge effects from AlInGaP material and cavity losses from colour conversion processes.
InGaN-based Red is attractive as it offers lower manufacturing costs, scalability to larger 200 mm or 300 mm wafers and better hot/cold factor over incumbent AlInGaP-based Red. However, achieving red spectral emission with InGaN material is challenging due to the high indium content inducing significant strain in the active region, subsequently reducing crystal quality and creating numerous defects. Plessey has successfully overcome these challenges by using a proprietary strain engineered active region to create an efficient InGaN Red LED.
