Detection of trap activation by ionizing radiation in SiO2 by spatially localized cathodoluminescence spectroscopy

Abstract

Microcathodoluminescence ͑CLS͒ spectroscopy is used to probe the effect of ionizing radiation on defects inside Al gate oxide structures. Micron-scale Al-SiO 2-Si capacitors exposed to 10 keV x-ray irradiation exhibit spatially localized CLS emissions characteristic of multiple deep level traps, including positively charged oxygen-deficient centers and nonbridging oxygen hole centers ͑NBOHC͒. Irradiation produces both increases and decreases in their relative emission intensities, depending on spatial location within the oxide. These changes result in a gradient of EЈ versus NBOHC defect densities across the oxide thickness between Al and Si interfaces. These results demonstrate that x-ray irradiation-induced deep level traps can be monitored spatially in metal-oxide-semiconductor gate structures, that x-ray irradiation produces separate increases or decreases in EЈ versus NBOHC defect densities, and that these changes vary with position within the oxides.

Defect Manipulation To Control ZnO Micro-/Nanowire-Metal Contacts

“…The pronounced 1.91 eV peak is characteristic of nonbonding oxygen hole center (NBOHC) defects, which are completely absent from spectra in Figures and S2. Another common SiO 2 defect termed E ′ frequently present in SiO 2 occurs at 2.7 eV , but is also not present in these spectra. Pt metal overlayers also do not contribute to the observed luminescence.…”

“…Another common SiO 2 defect termed E′ frequently present in SiO 2 occurs at 2.7 eV 23,39 but is also not present in these spectra. Pt metal overlayers also do not contribute to the observed luminescence.…”

Single Metal Ohmic and Rectifying Contacts to ZnO Nanowires: A Defect Based Approach

“…Phonon replicas associated with the 2.35 eV features can be observed at lower temperatures and defect densities . A 1.9 eV feature is associated with a common SiO 2 defect known as a non‐bridging oxygen hole center …”

Interface Trap Density Reduction for Al2O3/GaN (0001) Interfaces by Oxidizing Surface Preparation prior to Atomic Layer Deposition

“…The incident electron beam used in cathodoluminescence generates electron−hole pairs that induce electronic transitions with specific signatures of photon emission from deep levels and band edges. 40 The ability to tune the electron−hole generation depth by varying the accelerating voltage in CL measurement enables discrimination of the light emission signal from the bulk and near-interface regions of MOS structures.…”

“…Therefore, we investigated interface defects using a complementary and nondestructive technique, cathodoluminescence, that can provide an alternative insight into the energy states of these defects and their dependence on surface pretreatment prior to ALD of Al 2 O 3 on GaN. The incident electron beam used in cathodoluminescence generates electron–hole pairs that induce electronic transitions with specific signatures of photon emission from deep levels and band edges . The ability to tune the electron–hole generation depth by varying the accelerating voltage in CL measurement enables discrimination of the light emission signal from the bulk and near-interface regions of MOS structures.…”