Current conduction mechanism in TiO2 gate dielectrics
Electrical properties of titanium oxide (TiO2) deposited on strained-Si heterolayers by plasma enhanced chemical vapor deposition (PECVD) from an organo-metallic precursor titanium isopropoxide (TTIP), have been investigated in Al/TiO2/strained-Si structures by capacitancevoltage (CV) and currentvoltage (IV) measurements. For as-deposited layers, which exhibit high level of interface states and leakage current, both PooleFrenkel (PF) and Schottky emission (SE) effects govern the conduction mechanism. After post deposition annealing in pure nitrogen ambient at 400C, the conduction mechanism changes and the interface state density reduces by an order of magnitude. It is found that after annealing, only Schottky emission dominates the conduction mechanism at a low electric field.
tio2 strained-si schottky emission high-k poolefrenkel effect