A.M. Skvortsov, Huynh Cong Tu, R. A. Khaletskiy

St.Petersburg national research university of information technologies,

 mechanics and optics, Russia

Åffect of laser microstructuring on electrophysical properties of system SiO2/Si.

Laser surface microstructuring has been shown to be a clean and versatile surface structuring method, and it is effective and applicable to almost all solid materials [1]. Surface microstructuring leads to interesting and useful new features of materials such as low reflection [2], high light and electron emittance [3], special wetting properties, which enlarge their application domain [4]. As one of the most important semiconductors, silicon is widely used in microelectronics and optoelectronics. Irradiation of a silicon surface with laser pulses in various atmospheres can not only microstructure but also change its optical and electronic properties dramatically.

One of the basic materials, which plays an important role in microelectronics is a silicon dioxide thin film grown by thermal oxidation of the silicon substrate. In studying the effect of the laser radiation on the silicon dioxide-silicon (SiO2/Si) system new phenomena that stimulate increased interest in this problem have been found. For example, authors of work [5] note that under laser irradiation has been found the change of optical and electrical properties of SiO2 layer on Si single crystal. In our studies [6, 7] reported that under laser irradiation of SiO2/Si system new charges are induced in the oxide. It was shown that the change of electrophysical properties of SiO2/Si appears in areas remote from the direct exposure area to the laser beam. However till now less work has been done to reveal processes occurring in the system under ultrashort pulse laser irradiation. It is especially actual due to the fact that lasers are designed and manufactured with the new performance (high energy and pulse repetition rate).

In this work, the effect of irradiation on system SiO2/Si by pulsed ytterbium fiber laser type ILI-1-50 (λ=1062 nm) with the formation of mesh of slip lines on its electrophysical parameters has been investigated. It is shown that exposed to laser radiation in the silicon dioxide - silicon system there are structural changes that lead to the change of the electrophysical properties of SiO2/Si system. Changes in electrophysical properties of the oxide and the interface are more observed in the area of direct exposure to the laser beam on the silicon substrate where there are maximum structural changes of the silicon surface manifested in the form of a network of slip lines. It is found that there are laser-induced defects in areas remote from the irradiation zone.

References

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