Si(001) Surface Layer-by-Layer Oxidation Studied by Real-Time Photoelectron Spectroscopy using Synchrotron Radiation

Abstract

High-resolution O 1s and Si 2p photoelectron spectroscopy using synchrotron radiation was employed to clarify a layer-by-layer oxidation reaction mechanism on a Si(001) surface from the viewpoint of point defect generation due to an oxidation-induced strain at a SiO2/Si interface. The Siβ and Siα components in Si 2p3/2 spectra, which are assigned to the first and second strained Si layers, respectively, below the transition layer composed of suboxides, Si1+, Si2+, and Si3+, significantly decrease during the step-by-step temperature increase-enhanced growth of the second oxide layer. Because of the corresponding band bending changes measured using the O 1s peak position, which are caused by defect-related band gap states, the observed decreases in Siβ and Siα components, indicating a decrease in interfacial strain, are induced not only by the structural relaxation of a SiO2 network due to a thermal annealing effect, but also due to the generation of point defects at the SiO2/Si interface. Continuous band bending changes with the growth of the third oxide layer also suggest that the point defects are generated during oxide growth, whereas the Siβ and Siα components are maintained almost constant. On the basis of the observed interfacial strain and point defect generation changes, the layer-by-layer growth kinetics of the first, second and third oxide layers is discussed using a unified Si oxidation reaction model mediated by point defect generation at the SiO2/Si interface [S. Ogawa and Y. Takakuwa: Jpn. J. Appl. Phys. 45 (2006) 7063].

Effect of UV Irradiation on Threshold Voltage and Subthreshold Slope in Pentacene TFT

“…The relative peak positions of each bond state of Si-O were referred from previous reports. 10,11 The widths of all the peaks were simulated by the least-squares method. The treated SiO 2 surface shows higher Si 3+ , Si 0 peak intensities and lower Si 4+ , Si + intensities than those of the untreated one.…”

“…In the aspect of SiO 2 growth on the Si surface, Si + and Si 0 were located at the Si/SiO 2 interface, so it was considered that the reduction reaction from Si + to Si 0 was not directly related to the changes of device performances. 10,11 Compared with the untreated Au, UV-treated Au showed negligible changes in atomic compositions and bonding states. These results indicate that the improved device performances after UV treatment are mainly due to the change of the SiO 2 surface bond structures.…”

Self‐accelerating oxidation on Si(111)7 × 7 surfaces studied by real‐time photoelectron spectroscopy

“…n Si , n oxide , λ Si , and λ oxide are assumed to be 5.00 × 10 22 atoms/cm 3 , 2.28 × 10 22 atoms/cm 3 , 1.66 nm, and 2.00 nm, respectively. More details can be found elsewhere …”

“…The low‐binding‐energy shift was the compressive strain and the high‐binding‐energy shift was the tensile strain near the interface . In addition, the oxide growth rate on Si surfaces can also be obtained from time‐resolved measurements by XPS …”

Reaction Kinetics in the Rapid Oxide Growth on Si(001)-(2×1) Probed with Reflectance Difference Spectroscopy

“…In the study of the initial oxidation process on Si(001)-(2Â1), real-time measurements were performed by RDS/ SDR [3][4][5]15,16) and ultraviolet/X-ray photoemission spectroscopy (UPS/XPS) [17][18][19] and Auger electron spectroscopy (AES). 20,21) In this report, we demonstrate that reaction kinetics different from a simple Langmuirian kinetics is clearly identified with RDS.…”