Easily reproducible top-emitting organic light-emitting devices for microdisplays adapted to aluminum contact from the standard CMOS processes

Abstract

Organic light-emitting devices (OLEDs) on the silicon backplanes processed via the standard foundry complementary metal–oxide-semiconductor (CMOS) processes were developed with the state-of-the-art electrical doping technology to meet the optical and electrical requirements, resulting in high luminance (over 5000 cd/m2) for the green emissive OLED microdisplay. The unavoidable oxidized aluminium contact after the CMOS processes on the top layer of the pixel was found to significantly increase the driving voltage of the device (up to 1 V at 100 cd/m2 luminance). To aid in the extraction of the accurate device parameters for setting up an equivalent circuit, the reference top-emitting OLEDs without bottom metal contacts were deposited directly on interconnection-metal-only silicon substrates from the CMOS foundry. The distribution of the AlOx of the top-layer metal contact on silicon (the bottom anode of OLEDs) was confirmed by the X-ray photoelectron spectroscopy (XPS) depth profiles.