Contacting Diffusion with FIB for Backside Circuit Edit—Procedures and Material Analysis

The feasibility of low-ohmic FIB contacts to silicon with a localized silicidation was presented at ISTFA 2004 [1]. We have systematically explored options in contacting diffusions with FIB metal depositions directly. A demonstration of a 200nm x 200nm contact on source/drain diffusion level is given. The remaining article focuses on the properties of FIB deposited contacts on differently doped n-type Silicon. After the ion beam assisted platinum deposition a silicide was formed using a forming current in two configurations. The electrical properties of the contacts are compared to furnace anneal standards. Parameters of Schottky-barriers and thermal effects of the formation current are studied with numerical simulation. TEM images and material analysis of the low ohmic contacts show a Pt-silicide formed on a silicon surface with no visible defects. The findings indicate which process parameters need a more detailed investigation in order to establish values for a practical process.