Chemical Structure of Native Oxide Grown on Hydrogenterminated Silicon Surfaces

Abstract

Chemical bonding features and suboxide compositions in native oxide grown on chemically-cleaned hydrogen-terminated Si(100) surfaces stored in pure water have been studied by using surface sensitive infrared spectroscopy and x-ray photoelectron spectroscopy. The LO phonon peak for the native oxide is located at 1210cm-1 , which is shifted to a significantly lower wavenumber side than the ultrathin thermal oxide peak at 1250cm-1 . This is because an appreciable amount of SiHX bonds are incorporated in the native oxide/Si interface and such hydrogen termination in the network dramatically reduces strained bonds in the interface. Very weak Si 2 + suboxide signal from the oxide grown in pure water is also explained by the incorporated SiHx bonds which interrupt the Si 2 ÷ suboxide formation in the interface.

Evolution of a Native Oxide Layer at the a-Si:H/c-Si Interface and Its Influence on a Silicon Heterojunction Solar Cell

“…18−22 The vibration frequency of the Si−O−Si stretching mode (1232 cm −1 ) here is about 30 cm −1 higher compared with that of porous SiO 2 prepared by the liquidphase-deposition technique, 23 which may be affected by the bonded H atoms with SiH 2 and SiH configurations because H atom is more electronegative than Si atom. The spectrum in Figure 1a is in good agreement with a published result by Takakura et al 21 The schematic diagram of Bare is shown in Figure 1b. SE is a very sensitive and powerful tool to investigate ultrathin films; when the Bare was measured by SE in the clean atmosphere, the imaginary part of the pseudo dielectric function ε 2 systematically decreased as the exposure time increased, especially at photon energy higher than 3.6 eV, as shown in Figure 2a.…”

“…This peak can be assigned as SiH 2 bending mode. Another two peaks at 1095 and 1232 cm –1 are also observed; they are originated from interstitial oxygen and small-size (<λ/2π n m ) SiO 2 precipitates, respectively. − The vibration frequency of the Si–O–Si stretching mode (1232 cm –1 ) here is about 30 cm –1 higher compared with that of porous SiO 2 prepared by the liquid-phase-deposition technique, which may be affected by the bonded H atoms with SiH 2 and SiH configurations because H atom is more electronegative than Si atom. The spectrum in Figure a is in good agreement with a published result by Takakura et al The schematic diagram of Bare is shown in Figure b.…”

Environmental photostability of SF6-etched silicon nanocrystals

“…Fluorine segregates to the Si/SiO 2 interface and has the effect of reducing the generation rate of interface states and charge trapping as well as reducing plasma charging damage [64]. Some of the Si-O-Si bonds that form during oxidation of silicon are highly strained, especially for low-temperature oxidation [65], and so are susceptible to relaxation due to UV absorption or by proton insertion when exposed to water vapor. This relaxation process is believed to be associated with interface state formation, which leads to the formation of non-radiative pathways.…”