Review—Review of Research on AlGaN MOCVD Growth

Abstract

Due to the broad application prospects of optoelectronic devices and microwave devices at high temperature and power, the process of Metal Organic Chemical Vapor Deposition (MOCVD) of AlGaN of the key material AlGaN has been extensively researched in the past 30 years. In order to enhance the quality of AlGaN layers, researchers continuously analyzed their growth mechanism and optimized the growth process through experimental and theoretical studies. In this work, based on reviewing previous studies, we summarize the research progress for AlGaN grown by MOCVD and discuss the existing problems and future research priorities.

Monolayer‐Thick GaN/AlN Multilayer Heterostructures for Deep‐Ultraviolet Optoelectronics

“…Nevertheless, numerous groups have developed new equipment and various techniques for epitaxial growth of smooth and rather uniform Al-rich AlGaN layers using both MOCVD and MBE with plasma activation of molecular nitrogen (PA MBE) or thermal cracking of ammonia (NH 3 -MBE). [43][44][45][46][47][48][49] To achieve atomically a smooth surface morphology of AlGaN layers, it is necessary to ensure 2D growth mechanisms of these layers. The best results have been obtained by high-temperature MOCVD with a step-flow growth mode under properly managing the vapor supersaturation and the substrate misorientation angle.…”

Fully Relaxed, Crack-Free AlGaN with upto 50% Al Composition Grown on Porous GaN Pseudo-Substrate

“…In our previous work, a total of 1.3 µm thick elastically relaxed AlGaN with x Al = 0.18 was demonstrated using a growth temperature of 1080 • C and a mixture of hydrogen and nitrogen as the carrier gas [40]. To obtain good quality AlGaN films with a higher Al composition, the deposition temperature was increased to 1155 • C [42,43], and the NH 3 flow was decreased to 45 mmol/min from 178 mmol/min [40]. The molar flow of TMGa varied at 8.8-14.6 µmol/min and TMAl was in the range of 0.98-2.4 µmol/min, respectively.…”

Recent Advances in Packaging Technologies of AlGaN‐Based Deep Ultraviolet Light‐Emitting Diodes

“…In the past two decades, researchers have made a great deal of efforts to improve the EQE and WPE of AlGaN‐based UV LEDs, which have made great progress. [ 5–7,11,17–19,30,33–91 ] Figures and show the EQE and WPE for UV LEDs of different emission wavelengths by various research groups (till dated 2021/8/30) respectively. As shown in Figure 2, we can see that the EQE gradually decreased while the emission wavelength reduced from 400 to 200 nm.…”

“…External quantum efficiency (EQE) of different peak wavelengths by various research groups. [ 5–7,11,17–19,30,33–91 ] The corresponding full name of mentioned abbreviations are listed as following: Chinese Academy of Sciences (CAS), Ferdinand‐Braun‐Institut, Berlin (FBH‐Berlin), Hebei University of Technology (HEBUT), Huazhong University of Science and Technology (HUST), Fraunhofer Institute for Applied Solid State Physics (IAF), National Chiao Tung University (NCTU), Nippon Telegraph and Telephone Corporation (NTT), National Institute of Information and Communications Technology (NICT), Ohio State University (OSU), Palo Alto Research Center (PARC), Sensor Electronic Technology, Inc (SETi), Technische Universität Berlin (TU Berlin), University of Wisconsin–Madison (UM‐Madison), University of South Carolina (USC), University of Science and Technology of China (USTC).…”