Temperature dependence of gate currents in thin Ta_(2)O_(5) and TiO_(2) films

摘要

This letter reports our study of the temperature dependence of gate currents in thin Ta_(2)O_(5) and TiO_(2) films. The study was conducted (1) to study the conduction mechanisms and band alignments, and (2) to determine whether the gate leakage current is tolerable at high temperatures for either of these high-dielectric-constant (high-k) oxides. The I-V characteristics of these oxides were measured and analyzed over a wide temperature range from 25 to 400℃. Currents in Ta_(2)O_(5) samples exhibited stronger temperature dependence than those in TiO_(2) samples, especially at high fields, mainly due to a much smaller electron barrier height of Ta_(2)O_(5) over Si (0.28 eV) than that of TiO_(2) over Si (0.9 eV).