Photoemission Spectroscopy Study on Hydrogen Termination Effect on SiO₂/Si Structure Fabricated Using H⁺-Implanted Si Substrate

Abstract

Using proton (H+)-implanted silicon (Si) substrates, we clarified the effect of dangling bond termination by hydrogen on the interfacial strain in the silicon dioxide (SiO2)/Si system. The variations of the SiO2/Si interface structure caused by H+ implantation into a SiO2/Si sample and by hydrogen out-diffusion heat treatment were analyzed by high-resolution synchrotron radiation photoemission spectroscopy. We found that H+ implantation into the SiO2/Si sample [intentional generation of the interfacial dangling bonds] can increase the intensity of the strained-Si peaks in the Si 2p photoemission spectrum. In addition, our study revealed that the strained Si atom amount and dangling bond density are reduced by hydrogen out-diffusion heat treatment. These findings suggest that the increase/decrease in the dangling bond density by H atoms results in the increase/decrease in local strain field around a dangling bond, thereby changing the length of the Si–Si bonds beneath the SiO2/Si interface. Out-diffused hydrogen seems to play roles to not only reduce the dangling bond density but also relax the local strain at the SiO2/Si interface. The hydrogen termination effect is expected to have an advantage in structural stability in the SiO2/Si system as compared with the pure thermal termination effect.

Quantifying physical insights cooperatively with exhaustive search for Bayesian spectroscopy of X-ray photoelectron spectra

“…Hiroyuki Kumazoe 1,7* , Kazunori Iwamitsu 2 , Masaki Imamura 3 , Kazutoshi Takahashi 3 , Yoh-ichi Mototake 1 , Masato Okada 4,5 & Ichiro Akai 6,7 We analyzed the X-ray photoelectron spectra (XPS) of carbon 1s states in graphene and oxygenintercalated graphene grown on SiC(0001) using Bayesian spectroscopy. To realize highly accurate spectral decomposition of the XPS spectra, we proposed a framework for discovering physical constraints from the absence of prior quantified physical knowledge, in which we designed the prior probabilities based on the found constraints and the physically required conditions.…”

“…X-ray core-level photoelectron spectroscopy (XPS) is a popular and powerful tool for investigating the elemental composition of materials 1,2 . Especially, due to the short escape depth of photoelectrons excited by soft X-rays, XPS has been applied to various surface and interface analysis such as film thickness 3 , chemical states at surfaces or interfaces [4][5][6] , and atomic distortion at the interface 7 . The elemental information measured by XPS is revealed by line-shape analysis for the obtained spectrum.…”