Leakage current and electrical breakdown in metal-organic chemical vapor deposited TiO₂ dielectrics on silicon substrates

The leakage current through 190 Å TiO₂ deposited through metal-organic chemical vapor deposition on p-type silicon substrates has been measured as a function of temperature for both accumulation and inversion biases. When biased into inversion, the current initially is temperature independent suggesting that the current in this regime is dominated by tunneling. Above 100°C however it shows standard thermionic emission behavior up to 160°C where it again becomes temperature independent. The leakage under accumulation bias was independent of temperature up to 70°C while it shows standard thermionic emission behavior. The barrier for emission was between 0.94 and 1.0 eV for all samples measured. Both ramped voltage and time dependent dielectric breakdown measurements were carried out on these films. The lack of a breakdown event in constant current stress suggests that these films may be extremely robust as gate dielectrics in future metal-oxide-semiconductor field-effect transistors.