Annealing-temperature Dependence of Compositional Depth Profile and Chemical Structures of LaOx/ScOx/Si and ScOx/LaOx/Si Interfacial Transition Layer

Abstract

We have investigated the effects of post deposition annealing on chemical structures of 4 nm LaOx, 4 nm ScOx/Si, 2 nm LaOx/ 2 nm ScOx/Si and 2 nm ScOx/2 nm LaOx/Si interfaces by angleresolved X-ray photoemission spectroscopy. Analyses of Si 2s spectra show that the reactivity between ScOx and Si substrate is lower than that between LaOx and Si substrate. Analyses of O 1s spectra show that the absorption of moisture in the LaOx is suppressed by 2 nm ScOx/2 nm LaOx/Si structure. In addition, the electronic band structure of ScOx/Si(100) was determined.

(Invited) Study on Chemical Bonding States of High-k Gate Stacks for Advanced CMOS

“…In addition, the silicate formation for ScOx/LaOx/Si is also less than that for LaOx/Si. Moisture absorption of the water to the LaOx layer is suppressed by covering in ScOx layer based on the analyses of O 1s photoelectron spectra (11). This implies that the absorbed moisture in the LaOx film is diffused to high-κ/Si interface during PDA and the silicate is formed.…”

“…Influence of post deposition annealing on the compositional depth profiles and chemical bonding states of interfacial transition layers of laminating structure (11,13) The samples were prepared as follows. The n-Si(100) surfaces were cleaned in a mixed solution of H 2 SO 4 and H 2 O 2 (H 2 SO 4 :H 2 O 2 =4:1, SPM) followed by the treatment in 0.5% hydrofluoric acid solution to come up with hydrogen-terminated Si surfaces.…”

“…It was reported to be able to suppress the interfacial reaction by combining the scandium oxide with lanthanum oxide. (10,11) Recently, the leakage current at the EOT around 1.0 nm was suppressed by one order of magnitude by introducing the CeO 2 /La 2 O 3 stack, compared to that obtained in the La 2 O 3 single layer (9,12). It is one of the problems of La 2 O 3 to generate a fixed charge by the diffusion of oxygen in the La 2 O 3 film.…”

“…In the following the two topics will be reviewed. The first topic is the influence of post deposition annealing (abbreviated as PDA hereafter) on the compositional depth profiles and chemical bonding states of interfacial transition layers of laminating structure (LaOx/Si, ScOx/Si, LaOx/ScOx/Si, ScOx/LaOx/Si, CeOx/LaOx, and LaOx/CeOx) by ARXPS (11,13). The second topic is Hard X-ray(hν = 8 keV) excited ARXPS study on LaOx/Si structure with and without PDA (14).…”

Annealing-temperature Dependence of Compositional Depth Profiles and Chemical Bonding States of CeOx/LaOx/Si and LaOx/CeOx/Si Structure

“…It was reported to be able to suppress the interfacial reaction by combining the scandium oxide with lanthanum oxide. (10,11) Recently, the leakage current at the EOT around 1.0 nm was suppressed by one order of magnitude by introducing the CeO 2 /La 2 O 3 stack, compared to that obtained in the La 2 O 3 single layer (9,12). It is one of the problems of La 2 O 3 to generate a fixed charge by the diffusion of oxygen in the La 2 O 3 film.…”