Mechanism of leakage current reduction of tantalum oxide capacitors by titanium doping

In this letter, the authors will point out that defect states related to oxygen vacancies in tantalum oxide capacitors can be suppressed by titanium doping, resulting in significant leakage current reduction. The theory is that titanium forms an acceptor which can move at high temperature and neutralize other donors. However, defect states which cannot be suppressed by titanium doping were detected. These are explained by H2O-related contamination occurring at low temperature (< 400 degrees C) during the cooling down period. (c) 2007 American Institute of Physics.