Effects and mechanisms of nitrogen incorporation into hafnium oxide by plasma immersion implantation

Abstract

The physics and effects of nitrogen incorporation into HfO2 films were studied in detail. The authors found that only a trace amount (∼5%) of nitrogen can be introduced into the HfO2 films using plasma immersion ion-implantation technique, regardless of implantation dose. They proposed that the nitrogen incorporation is due to the filling of O vacancies (VO) and replacement of VO O neighbors in the bulk with nitrogen atoms. At the interface, the nitrogen atoms exist in the form of Hf–N and Si–N bonding, which significantly improve the interface properties of the HfO2∕Si structure. Temperature-dependent capacitance-voltage characteristics measurements indicate that both interface and oxide trap densities were greatly reduced with the incorporation of trace amount of nitrogen atoms.

Analysis of multilayered, nitrogen-doped aluminum oxide and hafnium oxide dielectric films for wide-temperature capacitor applications

“…The composition of the AlON films can be described as Al 2 O 3 with a small amount of nitrogen as an impurity, while the hafnium oxide films contain a slightly higher concentration of nitrogen. It is expected that the nitrogen concentration in the films would be low due to the high free energy of formation of the oxide compared to that of the nitride[13][14][15].XRD confirmed that the AlON films were amorphous and that the HfON films were partially crystalline(Figure 1). The peaks at 56° and 69.1° are from the Si substrate and the peak at 38.5° is from the bottom aluminum electrode.…”

Impact of carbon and nitrogen impurities in high-κ dielectrics on metal-oxide-semiconductor devices

“…This is consistent with experiments that report improved electrical properties when N is incorporated in HfO 2 /Si MOS structures. [13][14][15] The overall features of III-As-based MOS structures are very similar to the case of oxide/Si MOS structures. The (þ1/0) level of C Al and (0/-1) level of C Hf occur near the CBM of InGaAs (0.11-0.28 eV above), and hence those impurities may act as a source of border traps and/or increase leakage current.…”

“…11,12 Nitrogen, on the other hand, has been found to lower the density of interface states and improve dielectric strength. [13][14][15] The role of impurities in the electrical properties of Al 2 O 3 has not been well explored.…”

XPS Study of the Bonding Properties of Lanthanum Oxide/Silicon Interface with a Trace Amount of Nitrogen Incorporation

“…The buffer layer does improve the interface properties without scarifying the EOT. 19 This work further reports the nature of nitrogen incorporation and its effects on the interface properties of the La 2 O 3 /Si structure. Another measure is to modify the material properties of La 2 O 3 by introducing a foreign atom such as silicon, aluminum, and nitrogen into the bonding networks.…”

“…One of the techniques is to use a buffer layer such as Y 2 O 3 or CeO x between La 2 O 3 and the silicon substrate. 19,20 The introduced nitrogen atoms can fill up or disable the oxygen vacancies in the films. 13 However, the pronounced bulk trapping and the hygroscopic nature of the film remain unsolved.…”