Low-Destructive Processing of Single Crystal Aluminum Nitride Based on Sol-Gel Polishing Tool

Aluminum nitride (AlN) is a semiconductor material with the wide band gap. The requirement of the substrate for the semiconductor device is no surface damage. In this paper, based on the principle of the hydration reaction of aluminum nitride, the single crystal aluminum nitride was polished under dry conditions and wet conditions using a sol-gel (SG) tool. The abrasive used in the SG polishing tool was diamond with a particle size of 5 μm. Surface morphology of single crystal aluminum nitride was observed by scanning electron microscopy (SEM). Surface damage to the polished single crystal aluminum nitride was detected by 3D optical surface profiler, and the wear debris were analyzed by high resolution transmission electron microscopy (TEM). The product of the hydration reaction remaining on the aluminum nitride surface after polishing was studied by X-ray photoelectron spectroscopy. The results demonstrate that the removal rate of single crystal aluminum nitride by wet polishing is higher than that of dry polishing. The final roughness Sa of workpiece by dry polishing is 1.8-2.2 nm, and the final roughness Sa of workpiece by wet polishing is 1.1-1.2 nm. In addition, wear debris of workpiece by two polishing methods are amorphous.