Sheridan, T2015-12-132015-12-130022-3727http://hdl.handle.net/1885/93501We use a two-dimensional hybrid simulation (particle ions and Boltzmann electrons) to study sheath and ion dynamics around a small round hole in a flat, conducting plate following the application of a large, negative voltage pulse, such as might be encountered during plasma-based ion implantation. Results for hole radii of an eighth and half the ion-matrix overlap length and for depths of one, two and four times the radius are reported. For all these cases, it is found that the hole represents a small perturbation to a planar sheath since the sheath width is always greater than the hole radius. Consequently, most of the ions that enter the hole impact on its bottom at near normal angles; only a small fraction impact on the sidewall obliquely.Keywords: Computer simulation; Electric potential; Electrons; Plasma applications; Plasma sheaths; Positive ions; Surface treatment; Two dimensional; Boltzmann electrons; Ion dynamics; Ion matrix overlap length; Plasma based ion implantation; Ion implantation199910.1088/0022-3727/32/8/0082015-12-12