Single-crystalline semipolar GaN on Si(001) using a directional sputtered AlN intermediate layer

We obtained single-crystalline semipolar (101¯3)GaN on a nominal Si(001) substrate with sputtered AlN using the directional feature of sputtering. One dominated orientation of AlN was chosen to set Si[110] in the direction of the deposition. Microscopic characterizations using electron backscattering diffraction and macroscopic characterizations using X-ray diffraction revealed that GaN has an epitaxial relationship, which corresponds to [101¯3]GaN||[001]Si and [112¯0]GaN||[11¯0]Si. The density of the stacking fault in GaN with low temperature AlN insertion was estimated to be 3×104 cm−1 using transmission electron microscopy. Directional sputtering is a promising method that can be applied to the next generation of “GaN-on-Si” technologies for obtaining single-crystalline semipolar GaN on a Si(001) substrate.