X-Ray Reflectometry Study of the State of the Surface Layer of Polished Silicon Substrates Depending on the Methods of Their Cleaning
The state of the surface layer of polished silicon substrates and the effect of surface cleaning procedures, such as washing in an ultrasonic bath, etching, and vacuum annealing, was studied. The X-ray reflectivity technique was used to determine the root-mean-square roughness, thickness, and density of the damaged near-surface layer. It was shown that the substrates had a surface damaged layer 1.5 nm thick, which was most pronounced after annealing at 350°С. Based on the etching procedures and subsequent vacuum annealing, an approach is proposed for cleaning the surface from contaminants, a damaged layer and obtaining substrates with a root-mean-square roughness σz = 0.42 nm. This approach can be used, in particular, for the deposition of thin organic films.