Analytical TEM characterization of the interfacial layer between ALD HfO2 film and silicon substrate

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

“…In addition, they also demonstrated the evolutions of crystallite sizes, surface roughness, crystallographic orientation, as well as the growth rate of the films. Similar phenomenon has been reported by Lu et al by using HfI 4 and O 2 as precursor and oxidant [178]. According to the HRTEM image in Fig.…”

Complete prevention of reaction at HfO2/Si interfaces by 1nm silicon nitride layer

“…Hafnium dioxide (HfO 2 ) is one of the most promising materials for gate insulating layers to replace silicon dioxide (SiO 2 ) because of its high dielectric constant, high thermal stability, wide band-gap, etc. However, when HfO 2 is directly deposited on Si, an interfacial layer is formed, resulting in high interface state densities and in an increase of the effective oxide thickness (EOT) [1][2][3][4][5][6][7][8][9][10][11][12]. The composition of the interfacial layers strongly depends on the deposition conditions of HfO 2 films, i.e., SiO 2 [1][2][3][4][5][6], Hf silicate [7][8][9], SiO 2 rich hafnium silicate [4,10], and Hf silicide [11,12].…”

“…However, when HfO 2 is directly deposited on Si, an interfacial layer is formed, resulting in high interface state densities and in an increase of the effective oxide thickness (EOT) [1][2][3][4][5][6][7][8][9][10][11][12]. The composition of the interfacial layers strongly depends on the deposition conditions of HfO 2 films, i.e., SiO 2 [1][2][3][4][5][6], Hf silicate [7][8][9], SiO 2 rich hafnium silicate [4,10], and Hf silicide [11,12]. To prevent the formation of interfacial layers, SiO 2 [9,13], silicon oxynitride (SiON) [13][14][15][16], and silicon nitride (SiN) [15][16][17] are inserted between HfO 2 and Si.…”

“…In the case of NH 3 plasma, high concentration hydrogen atoms are incorporated, resulting in the formation of high density interfacial trap states [19][20][21]. Ultrathin SiON buffer layers formed by NH 3 and N 2 O plasma nitridation cannot prevent the interfacial reaction completely, leading to the formation of an Hf silicate interfacial layer [14]. The incomplete prevention of the interfacial reaction is possibly due to a low nitrogen concentration in the SiON layer.…”

Protective silicon coating for nanodiamonds using atomic layer deposition

“…Nevertheless, they are incapable of coating nanoparticles with continuous films or controlling the thickness of the films at nanometric scale. Recently, atomic layer deposition (ALD) has been reported to be an effective way of coating various substrates with conformal thin films [9][10][11][12][13]. Differed from other deposition methods, ALD consists of two basic steps that are repeated in every deposition cycle: (A) saturated adsorption of precursor gases or vapors onto the surface and (B) subsequent chemisorption or surface reaction of the precursors [14].…”