Monolithic Integration of GaN-Based Green Micro-LED and Quasi-Vertical MOSFET Utilizing a Hybrid Tunnel Junction
Yimeng Sang, Dongqi Zhang, Zhe Zhuang, Junchi Yu, Feifan Xu, Di Jiang, Ke Wang, Tao Tao, Xinran Wang, Rong Zhang, Bin Liu
Abstract
We demonstrated the monolithic integration of GaN-based driving metal-oxide-semiconductor field effect transistor (MOSFET) on micro-light-emitting diodes ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula> LEDs) by regrowing a hybrid tunnel junction (TJ) on top of a commercial green LED wafer. The hybrid TJ served not only as the current spreading layer for <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula> LEDs, but the n/p/n structure of the LED + TJ stack could also be utilized for fabricating a quasi-vertical driving MOSFET. The <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula> LED was connected to the MOSFET via the conductive n-GaN layer. By modulating the gate supply voltage, the MOSFET effectively controlled the injection current of the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula> LED, allowing for precise modulation of its output performance. The integrated 60- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}~\mu $ </tex-math></inline-formula> LED exhibited a high output power of 0.12 mW (~4.2 W/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) at a current of 0.3 mA (around 10 A/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) when the MOSFET was modulated with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}_{\text {DD}}$ </tex-math></inline-formula> = 5 V and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}_{\text {G}}$ </tex-math></inline-formula> = 16 V, demonstrating good <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula> LED performance and comparable driving capability to previous GaN-based MOSFETs and oxide-based thin film transistors. This work provides a new method for GaN FET/LED monolithic integration, which paves the way for potential applications in visible light communication and flexible <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula> LED displays.