Effect of nitrogen on band alignment in HfSiON gate dielectrics

Abstract

Nitridation of HfSiO films improves certain physical and electrical properties-when using gate stack layers-such as their crystallization temperature and their resistance to interdiffusion. We have studied the band alignment of HfSiO and HfSiON films by soft x-ray photoemission, oxygen K-edge x-ray absorption, and spectroscopic ellipsometry. Nitridation of HfSiO reduced the band gap by 1.50 eV± 0.05 eV, and the valence-and conduction-band offsets by 1.2 eV± 0.1 eV and 0.33 eV± 0.05 eV, respectively. Although the band-gap reduction should lead to increased leakage, the barrier heights are still sufficient for proposed near-future complementary metaloxide-semiconductor applications.

The effect of nitrogen concentration on the band gap and band offsets of HfOxNy gate dielectrics

“…12 Sayan et al have investigated the effect of nitrogen incorporation on the band offsets of HfSiO films and found that nitrogen incorporation reduced the band gap of the material by 1.50 eV, with the valence and conduction band offsets decreasing by 1.2 and 0.3 eV, respectively. 13 Although some of the aforementioned studies were carried out to understand the effect of nitrogen doping on the band gap and band offsets of high-k films, it is not clear if the doping concentration has any definite effect on the band gap and band offsets of HfO x N y films. In this letter, we attempted to determine if a definite relationship might exist between nitrogen concentration and band gap as well as band offsets of HfO x N y thin films.…”

Effect of nitrogen incorporation on the electronic structure and thermal stability of HfO2 gate dielectric

“…10 As a result atomic nitrogen can effectively block oxygen diffusion towards the interface and inhibit growth of interfacial SiO x layer. 11,12 However, through photoemission studies of band alignment of HfSiO and HfSiON, Sayan et al 13 found that nitridation could reduce the band gap, and both of valence and conduction band offsets of HfSiO relative to Si. It is expected that the nitridation of HfO 2 film on Si has a similar issue.…”

“…13 The nitridation of HfO 2 may have the same issue. In this report, the nitridation effect on the valence band spectra of HfO 2 film has been studied, as shown in Fig.…”

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

“…Metal oxide and oxynitride films make good dielectric candidates for thermally tolerant, low loss capacitor structures because of their wide band gap [3] and the polarizability of the metallic element [4]. The addition of nitrogen helps to inhibit crystallization during deposition, thereby improving the insulation properties [5][6][7].…”