Electrical properties of ultrathin HfO2 gate dielectrics on partially strain compensated SiGeC/Si heterostructures

Abstract

Ultrathin HfO 2 gate dielectrics have been deposited on strained Si 0.69 Ge 0.3 C 0.01 layers by rf magnetron sputtering. The polycrystalline HfO 2 film with a physical thickness of ∼6.5 nm and an amorphous interfacial layer with a physical thickness of ∼2.5 nm have been observed by high resolution transmission electron microscopy (HRTEM). The electrical properties have been studied using metaloxide-semiconductor (MOS) structures. The fabricated MOS capacitors on Si 0.69 Ge 0.3 C 0.01 show an equivalent oxide thickness (EOT) of 2.9 nm, with a low leakage current density of ∼4.5 × 10 −7 A/cm 2 at a gate voltage of -1.0 V. The fixed oxide charge and interface state densities are calculated to be 1.9 × 10 12 cm −2 and 3.3 × 10 11 cm −2 eV −1 , respectively. The temperature dependent gate leakage characteristics has been studied to establish the current transport mechanism in high-k HfO 2 gate dielectric to be Poole-Frenkel one. An improvement in electrical properties of HfO 2 gate dielectrics has been observed after post deposition annealing in O 2 and N 2 environments.

Investigations of Structural and Electrical Properties of ALD Films Formed with the Ozone Precursor

“…Furthermore, the improved quality of ALD materials has been shown to result in a significant smoothness level, lower leakage currents, and minor flat-band shift [ 20 ]. Ozone is characterized by a high electrochemical potential and high volatility.…”

A study on the characteristics of hydrated La2O3 thin films with different oxidation gases on the various annealing temperature

“…In order to solve these problems, the concept of introducing materials of high dielectric constant has been proposed. Some binary metal oxides, such as ZrO 2 [4] and HfO 2 , [5] have been widely studied for use as gate dielectrics. In addition, rare earth metal oxides such as La 2 O 3 [6] and Y 2 O 3 [7] have been reported as next generation high dielectric constant gate dielectrics.…”