Improvement of interfacial properties with interfacial layer in La2O3/Ge structure

O 3 -based atomic layer deposition of hexagonal La2O3 films on Si(100) and Ge(100) substrates

“…26,28 Because of the different growth temperatures and postdeposition annealing treatments employed in the different papers, it is not possible to make a direct comparison between the D it values. However, it is worth considering that Song et al 21,23 reported that, with vacuum annealing, it is possible to obtain a larger stack capacitance although associated with higher D it values. This observation is in line with our discussion about the efficiency of the vacuum annealing treatment in promoting, with a better efficiency, the formation of the h-La 2 O 3 phase.…”

“…18,19 In this context, a comparative study 20 between La 2 O 3 / Ge and La 2 O 3 / Si interfaces addressing IL thickness evolution after postdeposition annealing has revealed that the latter phenomenon is notably smaller for the Ge case than for the Si case, thus, indicating that the former interface might better serve future EOT scalability requirements than the latter one. Along these lines, a detailed investigation is mandatory in order to gain insight as to why low k values ͑k ϳ 14-22͒ compared to the expected value ͑k ϳ 27͒ corresponding to the pure h-La 2 O 3 phase 6,7 have been reported [20][21][22][23] so far for the La 2 O 3 / Ge stacks. Recently, lan-thanum germanate La x Ge y O z ͑LaGeO͒, which is almost unavoidably formed due to a strong and spontaneous reaction when La 2 O 3 comes in contact with the Ge surface, 24 has emerged as an attractive choice for high-k / Ge interfaces because of its beneficial role in defects passivation [24][25][26] and band offset enhancement.…”

“…37,38 Conversely, the spread regarding the methods for La 2 O 3 deposition on Ge substrates is narrower since the majority of published work is predominantly concerned with La 2 O 3 growth by electron beam evaporation 20,21 and molecular beam deposition. 24,[27][28][29]31 Nonetheless, it is widely acknowledged that atomic layer deposition ͑ALD͒ is the key tool to deposit innovative materials for fabricating a range of emerging nanostructures and nanodevices because it provides the capability to grow smooth and conformal films at relatively low temperatures and on large areas with an extremely accurate thickness control.…”

Thermally induced permittivity enhancement in La-doped ZrO2 grown by atomic layer deposition on Ge(100)

“…This value is in agreement with the presence of a comparatively denser germanate compound at the interface or with values proposed for germanates. 22,26 The use of these IL parameters in a two capacitors model provides a =32Ϯ 1 for the thick annealed films ͑19 and 29 nm͒ whereas for the thinner annealed La-ZrO 2 the is remarkably increased up to ϳ42Ϯ 1. Such result confirms that the 14 nm thick film is structurally different.…”

Impacts of Ti on electrical properties of Ge metal–oxide–semiconductor capacitors with ultrathin high-k LaTiON gate dielectric

“…Recently, it was reported that rare-earth metal oxides such as CeO 2 [13,14], Gd 2 O 3 [15] and Dy 2 O 3 [16] produced promising electrical properties when directly in contact with Ge. Especially, La 2 O 3 thin film shows many advantages, including low interface-states density, very small frequency dispersion and hysteresis due to formation of stable lanthanum germanate (La-Ge-O) [16][17][18]. However, a relatively low permittivity due to Ge diffusion into the highk dielectric prevents further decrease in equivalent oxide thickness [17].…”