Effect of thermal treatment on the band offsets and interfacial properties of HfO_xN_ygate dielectrics

Abstract

Band offsets and interfacial properties of HfOxNy films grown on Si(1 0 0) through radio-frequency reactive magnetron sputtering were investigated by x-ray photoelectron spectroscopy. The changes in the conduction band offset, the valence band offset, as well as in the interfacial properties were obtained as a function of the annealing temperature. The interfacial layer is unavoidably formed for the deposited films and the composition of the interfacial layer is most likely Hf-silicate and SiOx. With the increase in the annealing temperature, it is confirmed that the reaction between SiOx and HfOxNy films formed more Hf-silicate interfacial layer. The valence band offset (ΔEv) shifts upwards gradually with the increase in annealing temperature due to the decrease in N elements. After thermal treatment, the obtained conduction band offset (ΔEc) increased from 1.20 eV at 500 °C to 1.25 eV at 800 °C.

Integrations and challenges of novel high-k gate stacks in advanced CMOS technology

“…Among remaining oxides, Al 2 O 3 , Y 2 O 3 , ZrO 2 , and HfO 2 have been selected for research study for the past few years. Metal silicate, such as Hf, Zr, and Y has also attracted extensive attention due to their thermodynamic stability with Si [31][32][33][34][35].…”

“…Since accurate determination of the optical constant is an essential prerequisite for device simulations and gives the opportunity to improve material preparation, this necessitates the investigation of optical characteristics for Hf-based high-k gate dielectrics in the wide energy range. By spectroscopy ellipsometry (SE) data analysis on the basis of the accurately parameterized Taul-Lorentz model, the optical constants and the complex pseudo dielectric functions of HfO x N y films with nitrogen-incorporation content have been studied systematically [15,33,35,90]. Fig.…”

Characterization of HfO N thin film formation by in-situ plasma enhanced atomic layer deposition using NH3 and N2 plasmas

“…The degradation of electrical characteristics can be induced by incorporating nitrogen at the interface between dielectric thin films and the Si substrate [14,15]. Generally, there are several nitridation methods including chemical vapor deposition (CVD) [16], re-oxidation of HfN films formed by physical vapor deposition (PVD) [17], and thermal annealing with NH 3 [18] for HfO x N y thin films that have a high dielectric constant and thermal stability [9][10][11].…”

Hf-Based High-κ Dielectrics: A Review

“…Liu et al deposited HfO x N y samples on Si(100) by using radio-frequency reactive magnetron sputtering and have demonstrated that valence band offset and conduction band offset of the HfO x N y increases with annealing temperature. Table V summarizes the effect of annealing temperature on the band offsets of HfO x N y films [80]. [82].…”