Abstract
Micro-light-emitting diodes (mu LEDs) are semi-conductor devices that have been shown to have higher luminous efficacy, higher contrast ratio, and higher energy efficiency than existing mainstream technologies based on liquid crystals or organic LEDs (OLEDs). Portable display applications such as wearable devices and head-up display are some of the interesting applications of mu LED displays. However, this technology has not yet been mass-produced for commercial devices due to process yields, costs, and manufacturability issues. This article presents a novel technology for the heterogeneous integration of a mu LED matrix display with bipolar complementary metal-oxide-semi-conductor (CMOS) DMOS (BCD) circuits that could improve manufacturability by eliminating the need for a dedicated bond stack in the bump-bonding process. To validate the concept, custom high-performance, 2-D arrays of parallel-addressed GaN blue mu LEDs matrices were fabricated. The individual mu LED pixel diameters are 20 and 50 mu m, respectively, and the overall dimension of the array is 650 mu m(2). In addition, a mu LED display driver-integrated circuit (IC) with a compact size of 3x4.4 mm(2) has been designed, implemented, and verified experimentally for the mu LEDmatrices. Measuredoutput opticalpower-forwardbias current-forward bias voltage (P-I-V) curves of the individual mu LED pixel are shown. The 4 x 4 mu LED matrix has also been successfully driven using active-matrix driving and displaypicturesto demonstrate the function of active-matrix driving are presented.