Dry etching technique for microLED applications

Since the development of the blue LED in the latter years of last century, LED technology has revolutionised the display industry. Now with demands for small high resolution displays used for AR/VR/XR applications and as a competitor to OLEDs for use in watches and mobile phones, a concerted effort is being made to transfer this technology to the much smaller microLEDs, with typical dimensions in the range of 1 to 10 microns. This transfer is far from straightforward as size effects begin to dominate. Our discussion herein has explored various etching methodologies for GaN and AlInGaP mesas, isolation, and pillar etching related to LED or microLED applications. The excellence of these etching processes holds paramount importance in shaping the ultimate performance of microLED devices. Our presentation will elucidate strategies for achieving well controlled profile angles, smooth surface, and sidewall with optimised processes. OIPT has an ongoing programme investigating correction of size effects, for the transition to the smallest devices <5 microns, where the damage in sidewalls begins to dominate in a way that is not seen in typical larger devices.