Studies of charge carrier trapping and recombination processes in Si∕SiO2∕MgO structures using second-harmonic generation

Abstract

Effects of MgO deposition on Si∕SiO2 system and charge carrier trapping and recombination in Si∕SiO2∕MgO structures are studied using second-harmonic generation (SHG). An ultrafast 800nm laser was used both for multi-photon induced electron injection through the SiO2 into a potential well in the MgO, and for monitoring the time-dependent SHG signal, which is sensitive to the electric field at the Si∕SiO2 interface. Our results indicate that the MgO deposition introduces new trap states, and electrons trapped in the MgO transport more readily through the SiO2 than those in traps on the surface of SiO2. We attribute this to differences in trap energy levels and/or differences in process damage-induced defect densities in the SiO2.

Charge trapping defects in Si/SiO2/Hf(1−x)SixO2 film stacks characterized by spectroscopic second-harmonic generation

“…30,31 This mechanism cannot explain the present result, however, for three reasons. 30,31 This mechanism cannot explain the present result, however, for three reasons.…”

Optical second‐harmonic generation study of charge trapping dynamics in HfO2/SiO2 films on Si(100)

“…Since electrons and holes generate EFISH fields of opposite sign [10,11], we use increases or decreases of the total SHG signal to identify electrons or holes as the majority trapped species. Second, the timedependent EFISH generation method enables us to study charge dynamics separately in as-deposited and annealed samples.…”

First comparison of electric field induced second harmonic of near-infrared femtosecond laser pulses in reflection and transmission generated from Si/SiO2 interfaces of a silicon membrane

“…Optical second harmonic generation (SHG) is well known for its atomic scale surface and interface sensitivity if applied to centrosymmetric materials like silicon (Si), for which SHG is dipole forbidden in the bulk. It is contactless, non-intrusive with in situ abilities of monitoring electronic defects during UV irradiation [1], chemical contamination [2], interfacial roughness [3,4] and the dc electric field resulting from charge separation across the Si/SiO 2 interface [5][6][7][8][9][10]. In the presence of interfacial electric fields frequency conversion is enhanced significantly so that the electric field induced second harmonic (EFISH) generation process dominates [10].…”