High-performance III-nitride blue LEDs grown and fabricated on patterned Si substrates

摘要

InGaN/GaN based blue LEDs with 2-μm-thick crack-free GaN buffer layers were successfully grown and fabricated on patterned Si (111) substrates. The patterns on the substrates include 340 μm x 340 μm square islands, separated by 3-μm deep and 20 蘭 wide trenches, along the < 110 > and < 112 > crystalline orientations. In addition to using the patterned growth technique, thin AlN and SiN_x interlayers grown at high temperatures were also employed to partially release the residual stress and to further improve the crystalline quality. Blue LEDs of 300 x 300 μm~2 fabricated on the islands, without thinning and packaging, exhibited a high output power of around 0.7mW at a drive current of 20mA. Compared to III-nitride LEDs grown on sapphire substrates, the same LED structures grown on patterned Si substrates showed a few nm of red shift in emitting wavelength, suggesting some residual stress of GaN on patterned Si.