High-Pixel-Density 960 × 540 Flip-Chip AlGaInP Red MicroLED Display
Meng‐Chyi Wu, Zi-Liang Hsu, Cheng‐Yeu Wu
Abstract
This article reports the active matrix (AM) 630-nm red flip-chip <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$960\times540$ </tex-math></inline-formula> micro-light-emitting diode (MicroLED) displays with high pixels per inch (PPI) of 1600. A novel p-side-up AlGaInP thin-film structure by a wafer-transfer technique onto the sapphire substrate is proposed to fabricate the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$960\times540$ </tex-math></inline-formula> MicroLED array. In addition, the single pixel with a diameter of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10~\mu \text{m}$ </tex-math></inline-formula> on the MicroLED array exhibits excellent characteristics, including a forward voltage of 1.96 V at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$17.4~\mu \text{A}$ </tex-math></inline-formula> , an extremely low leakage current of 90 fA at −10 V, and a high light output power of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$94~\mu \text{W}$ </tex-math></inline-formula> at 1 mA. The highest external quantum efficiency (EQE) is 5.3% at 330 A/cm2 for the single pixel of MicroLED. The operability and lightening pixels of flip-chip bonding to AM driver IC analyzed by software image J are 80.21% and 415 808, respectively. Through flip-chip bonding technology, the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$960\times540$ </tex-math></inline-formula> MicroLED display can demonstrate the high-resolution graphic and video images. It is a prospective technology for the application of augmented and virtual realities (AR and VR) and optogenetic neural stimulation.