Thermal and electrical properties of TaN electrode on HfO2 gate dielectric

Ultra-thin hafnium-oxide gate dielectric film and TaN electrode film were deposited by using atomic layer deposition and DC magnetron sputter, respectively, and the thermal and electrical properties were investigated. In this article, it is shown that TaN on ALD-HfO2 has a midgap work function of ∼ 4.67 eV and no interaction occurs between gate and dielectric. Capacitance-voltage measurements show equivalent oxide thickness of about 1.5 nm for 5.0 nm HfO2 with TaN electrode. Also, the dielectric constant and the leakage current density of ALD-HfO2 film are 13.3 ∼ 16.3 and 1 X 10-6 A/cm2 at 1.0 V from flat band voltage, respectively. TEM showed that the interfaces of HfO2/Si and TaN/HfO2 are stable at least up to 600 .deg. C.