Galvanic corrosion characteristics of poly silicon–tantalum nitride couple immersed in dilute HF solutions

Galvanic corrosion characteristics between poly-Si and tantalum nitride (TaN) in dilute HF solutions (0.1 to 1%) have been investigated. Variables such as poly-Si to TaN area ratio, dissolved oxygen concentration in HF solutions and doping level of poly-Si were investigated. Extent of galvanic corrosion was directly measured as well as estimated using Tafel polarization. Morphological changes on poly-Si due to galvanic corrosion were characterized using Scanning Electron Microscopy. Increase in exposed cathode (TaN) area as well as aeration results in higher corrosion of poly-Si. In de-oxygenated HF solutions (less than 4 ppm of O2), irrespective of the area ratio, there appears to be no significant silicon loss.