Improving the structural performance of low-temperature sputtered AlN on silicon substrate

Preparing high-quality AlN films at low temperatures is always highly demanded in plenty of application-fields, despite the high temperature is always necessary to enable the AlN crystallization. Therefore, improving the structural properties at low temperature is still challenging in the field. In the present work, a metal organic chemical vapor deposition (MOCVD) grown AlN nucleation layer is employed to improve the crystallinity and morphology of sputtered AlN on 6-inch Si (111) substrate at temperatures even as low as 100 degrees C where it is not principally possible to achieve crystallization of sputtered AlN. When compared with the as-sputtered AlN prepared even at 650 degrees C, it is found that the full width at half maximum of AlN (002) x-ray rocking curves is intensively decreased to 0.96 degrees from 1.61 degrees, and such a reduction indicates that the screw dislocation density is decreased from 7.31 x 1010 down to 2.14 x 1010 cm-2. In addition to the crystallinity, the morphology is also obviously improved that the root-mean-square roughness is reduced from 4.99 nm down to 0.83 nm in a scanned area of 3 x 3 mu m2 through introducing AlN nucleation. Therefore, such a combination highlights the contribution of AlN nucleation grown by MOCVD in improving the structural properties of low-temperature sputtered AlN layer which is compatible with the manufacturing of Si integrated circuits.