Ion mixing of markers in SiO2 and Si

The amount of atomic mixing in amorphous SiO2 and Si is studied by measuring the redistribution of thin metal markers due to irradiation with 300-keV Xe+ ions. In SiO2, the mixing efficiency appears to be independent of the chemical nature of marker atoms and can be explained in terms of a linear cascade model. In Si, the mixing is found to correlate with thermally activated diffusivities of the marker species

Origin of Magnetic Circular Dichroism in GaMnAs: Giant Zeeman Splitting versus Spin Dependent Density of States

We present a unified interpretation of experimentally observed magnetic circular dichroism (MCD) in the ferromagnetic semiconductor (Ga,Mn)As, based on theoretical arguments, which demonstrates that MCD in this material arises primarily from a difference in the density of spin-up and spin-down states in the valence band brought about by the presence of the Mn impurity band, rather than being primarily due to the Zeeman splitting of electronic states.Comment: 4+ pages, 4 figure

Hydrogen gettering in annealed oxygen-implanted silicon

Hydrogen gettering by buried layers formed in oxygen-implanted silicon (Si:O prepared by O²⁺ implantation at the energy 200 keV and doses 10¹⁴ and 10¹⁷ cm⁻²) was investigated after annealing of Si:O at temperatures up to 1570 K, including also processing under enhanced hydrostatic pressure, up to 1.2 GPa. Depending on processing conditions, buried layers containing SiO₂₋x clusters and/or precipitates were formed. To produce hydrogen-rich Si:O,H structures, Si:O samples were subsequently treated in RF hydrogen plasma. As determined using secondary ion mass spectrometry, hydrogen was accumulated in sub-surface region as well as within implantation-disturbed areas. It has been found that hydrogen was still present in Si:O,H structures formed by oxygen implantation with the dose D = 10⁷ cm⁻² even after post-implantation annealing up to 873 K. It is concluded that hydrogen accumulation within the disturbed areas in Si:O as well as in SOI structures can be used for recognition of defects

Observation of surface states on heavily indium doped SnTe(111), a superconducting topological crystalline insulator

The topological crystalline insulator tin telluride is known to host superconductivity when doped with indium (Sn$_{1-x}$In$_{x}$Te), and for low indium contents ($x=0.04$) it is known that the topological surface states are preserved. Here we present the growth, characterization and angle resolved photoemission spectroscopy analysis of samples with much heavier In doping (up to $x\approx0.4$), a regime where the superconducting temperature is increased nearly fourfold. We demonstrate that despite strong p-type doping, Dirac-like surface states persist

Microstructure and Thermal Stability of Transition Metal Nitrides and Borides on GaN

Microstructure and thermal stability of ZrN/ZrB2 bilayer deposited on GaN have been studied using transmission electron microscopy methods (TEM) and secondary ion mass spectrometry (SIMS). It has been demonstrated that annealing of the contact structure at 1100 C in N2 atmosphere does not lead to any observable metal/ semiconductor interaction. In contrast, a failure of the integrity of ZrN/ZrB2 metallization at 800 C, when the heat treatment is performed in O2 ambient has been observed

MICROSTRUCTURE AND THERMAL STABILITY OF TRANSITION METAL NITRIDES AND BORIDES ON GaN

ABSTRACT Microstructure and thermal stability of ZrN/ZrB 2 bilayer deposited on GaN have been studied using transmission electron microscopy methods (TEM) and secondary ion mass spectrometry (SIMS). It has been demonstrated that annealing of the contact structure at 1100 0 C in N 2 atmosphere does not lead to any observable metal/ semiconductor interaction. In contrast, a failure of the integrity of ZrN/ZrB 2 metallization at 800 0 C, when the heat treatment is performed in O 2 ambient has been observed

Defects in high temperature and high pressure processed Si:N revealed by deuterium plasma treatment

Deuterium is accumulated by defects in nitrogen-implanted silicon (Si:N). This effect is investigated for Si:N processed at HT ≤ 1400 K, also under enhanced hydrostatic pressure, HP ≤ 1.1 GPa. Si:N was prepared from Czochralski grown silicon by N₂⁺ implantation at E = 140 keV with nitrogen doses, DN = 1–1.8•10¹⁸ cm⁻². Si:N was subsequently processed in RF deuterium plasma to prepare Si:N,D. Si:N and Si:N,D were investigated by Transmission Electron Microscopy (TEM), X-ray and Secondary Ion Mass Spec- trometry (SIMS) methods, also after additional annealing at 723 K. In heavily implanted Si:N (DN = 1.8•1010¹⁸ cm⁻²), plasma treatment leads to deuterium pile up to сD1 = 2•10²¹ cm⁻³ at a depth, d = 50 nm, while, at d = 80–250 nm, deuterium concentration is practically constant with сD2 = 1•10²¹ cm⁻³. This suggests dominating accumulation of deuterium within the bubble-containing areas. Determination of deuterium depth profiles in Si:N,D can reveal implantation- and processing-induced defects.В работе рассмотрены эффекты влияния обработки температурным отжигом (до 1400 K) и гидростатическим давлением (до 1.1 GPa) на дефектный состав SOI-структур (silicon-on-insulator) на основе образцов Si:N – материала, широко используемого в полупроводниковых технологиях. Были получены новые данные, свидетельствующие об образовании скрытых дефектосодержащих слоев в образцах кремния, имплантированного азотом, и подвергнутых обработке высокими температурами и давлениями. Такие структуры становятся центрами абсорбции дейтерия из плазмы – его накопление и распределение внутри образца зависят от микроструктуры материала. Таким образом, показано, что обработка в дейтериевой плазме с дальнейшим определением концентрационных профилей по глубине образца может быть полезной для оценки микроструктурыУ роботі розглянуто ефекти впливу обробки температурним відпалом (до 1400 K) і гідростатичним тиском (до 1.1 GPa) на дефектний склад SOI-структур (silicon-oninsulator) на основі зразків Si:N – матеріалу, широко використовуваного в напівпровідникових технологіях. Було отримано нові дані, що свідчать про утворення прихованих дефектовміщуючих шарів в зразках кремнію, імплантованого азотом, підданих обробці високими температурами та тиском. Такі структури стають центрами абсорбції дейтерію з плазми – його накопичення і розподіл усередині зразка залежать від мікроструктури матеріалу. Таким чином, показано, що обробка в дейтерієвій плазмі з подальшим визначенням концентраційних профілів по глибині зразка може бути корисною для оцінки мікроструктури Si:N-зразка, особливо зважаючи на потенційну застосовність в SOI-технологіях

Solid state doping of CdxHg₁₋xTe epitaxial layers with elements of V group

Presented here are the results of studying the controlled doping with elements of V group of the periodic table, arsenic As and antimony Sb, of narrow gap CdxHg₁₋xTe epitaxial layers during the isothermal growth from the vapour phase by the evaporation-condensation-diffusion method. Three types of impurity sources have been used for solid state doping: homogeneously doped with As(Sb) single crystal substrates of CdTe, As doped buffer CdyHg₁₋yTe (y > x) epitaxial layers obtained by RF sputtering in mercury glow discharge onto undoped CdTe substrates, and As(Sb) implanted undoped CdTe substrates. The results of comparative analysis of galvano-magnetic measurements and SIMS spectra indicated very high, practically nearly ~100 %, electrical activity of dopants in the CdxHg₁₋xTe epitaxially grown layers

Resonant Photoemission Spectroscopy study on the contribution of the Yb4f states to the electronic structure of ZnO

The electronic structure of Yb implanted ZnO has been studied by the resonant photoemission spectroscopy (RPES). The contribution of Yb 4f partial density of states (PDOS) is predominant in the binding energy (BE) about 7.5 and ~11.7 eV below the VB maximum. At the resonance energy, around 182 eV, the multiplet structure with the highest BE shows the strongest resonance (around 11.7 eV) that corresponds to the 1I multiplet which is almost exclusively responsible for this resonance, while 3H and 3F states are responsible for the resonance around 7.5 eV. It was also found that the Yb 4f PDOS distribution shows some similarity to Yb2O3