Deposition of ultrathin parylene C films in the range of 18nm to 142nm: Controlling the layer thickness and assessing the closeness of the deposited films

Abstract In this work we describe the deposition of ultrathin parylene C films in the range of 18 nm to 142 nm. Experimental results were obtained from measurements with a commercially available parylene deposition system which was equipped with a quartz crystal microbalance in order to monitor the thickness of the applied layers as well as the deposition rate in real time during the deposition process. This paper will supply the data required to conveniently reproduce the deposition of ultrathin films in the range of well below 100 nm. Furthermore we describe a simple and robust method to test if the applied parylene layers are closed which may be an important aspect to consider if ultrathin layers are to be used as protective coatings or the like. For an exemplary planar electrode structure, we have found a parylene layer of 35 nm to be the thinnest possible closed layer.