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MicroLED displays fabricated from compound semiconductor materials are a disruptive new technology offering advantages in efficiency, brightness, resolution and power consumption over incumbent LCD and OLED approaches. Today, such displays are assembled from arrays of micron sized emitters, made from traditional LED materials such as GaN (blue/green) and red (GaAs). And whilst an all GaN RBG solution remains the goal of the industry, this affording many advantages in display manufacture, producing high efficiency emitters at longer wavelength remains a challenge in GaN, so instead, device manufacturers use indium gallium phosphide (InGaP) to fabricate red microLEDs. In this work we present on a new 200 mm wafer platforms form for red microLED epitaxy where active structures are deposited on to CMOS fab compatible germanium substrates. Germanium is an excellent substrate starting material for epitaxial growth given it is lattice matching to GaAs, very high levels of crystal quality as well as mechanical strength and flatness. Here we compare the quality and performance of microLED devices grown on both GaAs and Ge and discuss the fab adoption strategies which are creating opportunities for the insertion of Ge based microLEDs into RBG displays We also discuss how these results create a path for large-scale microLED production on 300 mm platforms, integrated with CMOS backplanes to deliver the low cost, scaled approach which will be essential for the mass adoption of compound semiconductor based microLED displays.
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