First-Principles Calculations of Silicon Interstitial Defects at the Amorphous-SiO₂/Si Interface

Abstract

The migration barriers and formation energies of the silicon interstitials in an amorphous-SiO2/Si (a-SiO2/Si) interface are investigated in this work. The migration dynamics and energy profiles of the interstitials in the sublayers and the a-SiO2/Si interface are compared using the CI-NEB method. The results indicate that the neutral interstitial defects may migrate into a-SiO2/Si interface via several low-barrier channels, and get trapped at the interface because of the high energy barrier of the reverse migration. In addition, the formation energies and the charge transition levels of the interstitial defects at the a-SiO2/Si interface are also calculated with sophisticated corrections. The classical electrostatic calculation based on the finite element method is introduced to correct the long-range Coulomb interactions between the charged defect and its periodic images. The formation energy of the neutral interstitial defect shows dependence on the layer depth beneath the interface due to the unevenly distributed strain. The neutral interstitials on the H and split-⟨110⟩ sites are close in energy and are 0.2–1.3 eV higher than those on the split-⟨111⟩. Besides, the tetrahedral site is the most stable configuration in the double-positive charge state. In fact, the stable site for the interstitial silicon in the a-SiO2/Si interface depends on the relative position of the Fermi level and the interfacial strain.

Mechanism of the Heterogeneous Reduction of NO on a Sodium-Doped Char Surface: A First-Principles Study

“…In this research, the computational methods are very similar to those in the previous studies . All the calculations were performed with the Dmol in the Materials Studio using the DFT. − The GGA (generalized gradient approximation)–PBE (Perdew–Burke–Ernzerhof method) functional was used to describe the electron exchange–correlation potential. The double numerical polarized basis set with polarization functions was used to described the wave functions of the valence electron, and a real space cutoff of 0.45 nm was used.…”

Radiative and Magnetically Stimulated Evolution of Nanostructured Complexes in Silicon Surface Layers

“…Together with the oxygen and hydrogen atoms that are present in the dielectric layer, they can form electrically active complexes [31].…”

“…Small external factors can also stimulate the restructuring processes of existing nanoscale complexes and their clusters in semiconductor structures. This is mainly due to the excitation of the electronic subsystems of defects that exist on the silicon surface and at the Si-SiO 2 boundary [30][31][32][33][34][35][36]. In particular, small doses of ionizing radiation can cause the generation of non-equilibrium electrons and holes, which can be captured by defective complexes [30][31][32].…”

“…This is mainly due to the excitation of the electronic subsystems of defects that exist on the silicon surface and at the Si-SiO 2 boundary [30][31][32][33][34][35][36]. In particular, small doses of ionizing radiation can cause the generation of non-equilibrium electrons and holes, which can be captured by defective complexes [30][31][32]. A weak magnetic field can stimulate the reorientation of the electron spin of the atomic defects [33][34][35][36].…”

RADIATIVE AND MAGNETICALLY STIMULATED CHANGE OF THE ELECTRICAL PROPERTIES OF THE SiO2-Si STRUCTURE WITH A HIGH CONTENT OF DISLOCATION COMPLEXES

“…Разом з тим, технологічні операції виготовлення електронних пристроїв [10,11], експлуатація в екстремальних зовнішніх полях [12] можуть стимулювати створення внутрішніх дефектних комплексів на онові власних точкових дефектів (вакансій та міжвузлових атомів кремнію) [13] та їх подальшу взаємодію з дислокаціями та кластеризацію [14].…”