High growth temperature for AlN by jet stream gas flow metalorganic vapor phase epitaxy

Abstract

Deep ultraviolet light-emitting diodes have attracted considerable attention for realizing virus inactivation applications. The UV-LEDs use the AlN underlying layer and the plane sapphire substrate. However, the low growth temperature in AlN underlying layer is grown by limited growth temperature in conventional MOVPE, and high temperature is preferable for AlN growth. Furthermore, the AlN underlying layer has many dislocations owing to the active layer in the device region when the flat sapphire substrate was used with a dislocation value of > 109 cm−2. We showed the high-temperature crystal growth of AlN with a temperature of 1700 °C by high temperature and gas flow velocity MOVPE. The achieved dislocation density was ~ 4 × 108 cm−2. Additionally, this data means the low dislocation densities in the AlN layer with a growth time of only 15 min and a dislocation density of < 1 × 109 cm−2 are obtained. The AlN growth temperature exceeding 1550 °C decreases the growth rate. These results indicate desorption from the surface of the substrate in a hydrogen atmosphere. Furthermore, the characteristic dislocation behavior of AlN in high-temperature growth at 1700 °C was elucidated from TEM images.

Investigation of V/III ratio dependencies for optimizing AlN growth during reduced parasitic reaction in metalorganic vapor phase epitaxy

“…Several researchers have avoided these phenomena by reducing the ammonia gas flow 13 , 20 , 21 ; however, AlN growth conditions are easily influenced by parasitic reactions. As previously mentioned, Our MOVPE grow AlN at high temperatures without any influence of parasitic reactions 11 , 12 . Therefore, we have investigated the effect of V/III ratio dependencies for optimizing AlN growth without the effects of parasitic reactions by using jet stream gas flow MOVPE.…”

“…The difference in the behavior of the threading dislocations could be due to the growth models in Fig. 5 b. High-temperature growth at 1700 °C is the region wherein the growth rate decreases 12 . This could be adatom desorption during migration due to the high thermal kinetic energy.…”

“…However, the typical AlN growth temperature achieved by conventional MOVPE is less than 1400 ℃ because high temperatures above 1500 ℃ are rarely achieved in terms of equipment materials and process control. Recently, an MOVPE system with a high temperature for AlN has been developed and high-temperature growth can be realized over 1700 ℃ 11 , 12 .…”

Van der Waals Epitaxy Growth and Characterization of 7:7:8 Commensurate Heterointerfaces between h-AlN and Two-Dimensional WS2/c-Al2O3

“…The 2D-WS 2 provides a flat surface with a well-defined crystal lattice, which serves as a template for the growth of the AlN film. Additionally, the AlN films were grown at 800 °C, a temperature lower than that reported in previous works . We also investigated the interface between AlN and WS 2 , as well as the effect of interfacial properties on the performance of the heterostructure, using various analyses such as X-ray diffraction (XRD) and transmission electron microscopy (TEM).…”

Temperature dependence of electrical characteristics of Si-implanted AlN layers on sapphire substrates

“…High-quality AlN layers have been grown on Si, sapphire, and SiC substrates by metal-organic chemical-vapor deposition (MOCVD), [9][10][11][12][13] molecular-beam epitaxy (MBE), [14][15][16] sputtering, 17) and hydride vapor epitaxy (HVPE). 18,19) Si can be used as an n-type dopant of AlN.…”