  Ultrathin aluminum nitride (AlN) films are of great interest for integration
into nanoelectromechanical systems for actuation and sensing. Given the direct
relationship between crystallographic texture and piezoelectric response, x-ray
diffraction has become an important metrology step. However, signals from
layers deposited below the piezoelectric (PZE) AlN thin film may skew the
crystallographic analysis and give misleading results. In this work, we compare
the use of a Ti or AlN seed layer on the crystallographic quality of PZE AlN.
We also analyze the influence of several AlN seed layer thicknesses on the
rocking curve FWHM of PZE AlN and demonstrate an larger effect of the AlN seed
layer on the {\theta}-2{\theta} AlN <0002> crystallographic peak for increasing
AlN seed layer thickness.
