Reduction of parasitic reaction in high-temperature AlN growth by jet stream gas flow metal–organic vapor phase epitaxy

Abstract

AlGaN-based deep ultraviolet light-emitting diodes (LEDs) have a wide range of applications such as medical diagnostics, gas sensing, and water sterilization. Metal–organic vapor phase epitaxy (MOVPE) method is used for the growth of all-in-one structures, including doped layer and thin multilayers, using metal–organic and gas source raw materials for semiconductor devices. For AlN growth with high crystalline quality, high temperature is necessary to promote the surface migration of Al atoms and Al-free radicals. However, increase in temperature generates parasitic gas-phase prereactions such as adduct formation. In this work, AlN growth at 1500 °C by a stable vapor phase reaction has been achieved by jet stream gas flow metal–organic vapor phase epitaxy. The AlN growth rate increases with gas flow velocity and saturates at ~ 10 m/s at room temperature. Moreover, it is constant at an ammonia flow rate at a V/III ratio from 50 to 220. These results demonstrate the reduction in adduct formation, which is a typical issue with the vapor phase reaction between triethylaluminum and ammonia. The developed method provides the in-plane uniformity of AlN thickness within 5%, a low concentration of unintentionally doped impurities, smooth surface, and decrease in dislocation density because of the suppression of parasitic reactions.

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

“…The TMA raw material may accelerate the reaction with ammonia during transit by increasing the growth temperature 28 . Subsequently, these reactions are not contributed to an AlN growth in case of the formation of polymerization 23 , 24 . Moreover, the other one is the desorption of the Al adatom.…”

“…The MOVPE system reported in a previous study 23 was used. The TMA and ammonia were used as aluminum and nitrogen precursors.…”

“…However, this approach cannot be continuously grown in the device structure and requires renewal by eliminating it from the chamber. Recently, our group developed a growth approach with a low-parasitic reaction at a temperature of 1500 °C by metal–organic vapor phase epitaxy (MOVPE) imitating jet gas stream 23 .…”

“…However, this approach cannot be continuously grown in the device structure and requires renewal by eliminating it from the chamber. Recently, our group developed a growth approach with a low-parasitic reaction at a temperature of 1500 °C by metal-organic vapor phase epitaxy (MOVPE) imitating jet gas stream 23 .This study evaluated high-temperature growth in AlN by Jet stream gas flow MOVPE. Furthermore, the dislocation behavior of the grown AlN was analyzed by Transmission Electron Microscope (TEM).…”

“…The realization of high temperature for AlN growth by MOVPE. To realize high temperatures for AlN growth on the c-plane sapphire substrate, we used Jet stream gas flow MOVPE 23 . Firstly, optimized growth temperature in AlN was explored.…”