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

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 degrees C by high temperature and gas flow velocity MOVPE. The achieved dislocation density was similar to 4 x-10(8)-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 x-10(9)-cm(-2) are obtained. The AlN growth temperature exceeding 1550 degrees 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 degrees C was elucidated from TEM images.

Automated summary

This article discusses the use of deep ultraviolet light-emitting diodes for virus inactivation applications. It was found that the growth temperature of the AlN underlying layer was limited in conventional MOVPE methods, and using a flat sapphire substrate led to a high density of dislocations in the AlN layer. By utilizing high temperature and gas flow velocity MOVPE, high-temperature crystal growth of AlN at 1700 degrees C was achieved. The study also observed a decrease in growth rate at AlN growth temperatures exceeding 1550 degrees C.