Effect Of Low-temperature Annealing Research Articles

Effect of low temperature annealing on the electrical properties of an MOS capacitor with a HfO2 dielectric and a TiN metal gate

The effects of low temperature annealing, such as post high-k dielectric deposition annealing (PDA), post metal annealing (PMA) and forming gas annealing (FGA) on the electrical characteristics of a metal—oxide—semiconductor (MOS) capacitor with a TiN metal gate and a HfO2 dielectric are systematically investigated. It can be found that the low temperature annealing can improve the capacitance—voltage hysteresis performance significantly at the cost of increasing gate leakage current. Moreover, FGA could effectively decrease the interfacial state density and oxygen vacancy density, and PDA could make the flat band positively shift which is suitable for P-type MOSs.

The effect of low-temperature annealing on the electrical properties of the p-type cadmium–mercury–tellurium heterostructures grown by molecular beam epitaxy

The effect of low-temperature annealing on the electrical properties of the p-type cadmium–mercury–tellurium heterostructures grown by molecular beam epitaxy

Quasi-equilibrium size distribution of subcritical nuclei in amorphous phase change AgIn-Sb2Te

We investigate the effect of low temperature annealing or of extended storage at room temperature on the subsequent nucleation behavior of amorphous AgIn-incorporated Sb2Te (AIST), a material for phase change memories. Time-resolved reflectivity measurements during pulsed laser crystallization reveal the rates of solid-phase transformation, while fluctuation transmission electron microscopy detects the nanoscale order in the amorphous phase prior to crystallization. The nanoscale order is postulated to consist of subcritical nuclei that coarsen upon annealing at temperatures ranging from 25 °C (for months) or 100 °C (for hours). Samples that have been annealed remain fully amorphous as evaluated by conventional diffraction experiments. Shorter nucleation times are consistently associated with the observation of increased nanoscale order. The effect of annealing is observed to saturate: there is no further reduction in nucleation time or increase in nanoscale order for annealing at 100 °C beyond three hours. This result supports the general prediction of classical nucleation theory that the size distribution of subcritical nuclei increases from the as-deposited state to a quasi-equilibrium.

Raman spectroscopy for the study of reduction mechanisms and optimization of conductivity in graphene oxide thin films

Highly reduced few-layer graphene oxide films with conductivities of up to 500 S cm−1 are obtained. The thin films with an optimized compromise between sheet resistance (3.1 kΩ sq−1) and transparency (around 80% to 90%) are suitable for touch screens and transparent electrodes in OLEDs. We discuss the effects of low temperature annealing and chemical reduction on the properties of the films and present an optimized reduction process that allows the original 2D/G Raman intensity ratio of few-layer graphene to be recovered. The Raman spectrum of graphene oxide is found to be only related to oxygen-free graphene-like regions with Raman bands at 1130 and 3155 cm−1 that probably involve C–H vibrations of rings and edges, while a band at 1700 cm−1 is assigned to irregular rings such as Stone Wales defects. All the bands involve resonant Raman processes and disappear in highly reduced samples. Clear correlations of the D band width with the sp2 content in thin films and resistivity have been observed, indicating that this is a good Raman parameter for evaluating the quality of the samples. The structural defects produced by the release of embedded water and some of the oxygen functional groups during annealing are detrimental for intra-grain conductivity but greatly enhance inter-grain connectivity.

Microwave Annealing of Phosphorus and Cluster Carbon Implanted (100) and (110) Si

Effects of low-temperature (≈500°C) microwave annealing (MWA) of Cluster-Carbon (C7) and Phosphorus implants are compared with rapid thermal annealing (RTA) at 900 and 1000°C for (100) and (110)-Si substrates. MWA annealing resulted in high levels of substitutional Carbon, 1.57% for (100)Si and 0.99% for (110)Si for C7 implants. Addition of high-dose Phosphorus implants resulted in lower but still useful substitutional Carbon levels, 1.44% for (100)Si and 0.68% for (110)Si after MWA. RTA annealing at higher temperatures resulted in greatly reduced substitutional Carbon levels and deeper Phosphorus junctions. The effects of subsequent anneals by MWA and RTA methods are reported. MWA is shown to be a promising method for high-channel tensile strain in nMOSFETs with a substantially lower thermal budget than RTA.

The effect of annealing conditions on the adhesive properties of TiN coatings

The effect of low-temperature annealing on the adhesion strength and coefficient of friction of TiN coatings deposited on austenitic stainless steel by the vacuum-arc method is studied. The behavior of the coefficient of friction of titanium nitride upon annealing in air is discussed. It is shown that the adhesion strength of TiN coatings does not depend on annealing conditions.

Effect of annealing on the spectra of nuclear quadrupole resonance in gallium-indium selenides and characteristics of structures based on these materials

The results of studying the effect of low-temperature annealing (at temperatures no higher than 250°C) on the spectra of nuclear quadrupole resonance in layered GaSe and InSe single-crystal semiconductors are reported. The electrical and photoelectric characteristics of the p-GaSe-n-InSe structures have also been studied. It is shown that, as the annealing temperature is lowered to room temperature, the quality of the samples improves due to a decrease in the defect concentration in the crystals and due to ordering in a system of polytypes. The temperature conditions for the heat treatments, at which the main parameters of the heterojunction are improved, are determined. Mechanisms affecting the behavior of the p-GaSe-n-InSe structure during the course of annealing are discussed.

Effects of Low Temperature Electronic Cyclotron Resonance Hydrogen Plasma Treatment and Annealing on the Electrical Properties of Ti and Ni Contacts to 4H-SiC

Effects of Low Temperature Electronic Cyclotron Resonance Hydrogen Plasma Treatment and Annealing on the Electrical Properties of Ti and Ni Contacts to 4H-SiC

Effects of Low Temperature Electronic Cyclotron Resonance Hydrogen Plasma Treatment and Annealing on the Electrical Properties of Ti and Ni Contacts to 4H-SiC

The effects of low temperature electronic cyclotron resonance microwave hydrogen plasma pretreatment and post-annealing on the electrical properties of Ti and Ni contacts to 4H-SiC were investigated. The HPT improves the Ohmic behavior of Ti/4H-SiC contact significantly. In contrast, it remarkably enhances the rectifying behavior of Ni/4H-SiC contact. The properties of Ti Ohmic contact and Ni rectifying contact improve with increasing annealing temperature up to 400 °C. However, they are deteriorated above 400 °C. X-ray photoelectron spectroscopy measurements confirm that the surface Fermi level (EFs) moves toward the conduction band edge by the HPT. It almost attains the bulk Femi level position after annealing at 400 °C with the surface states density (Ds) as low as 4.43×1011 cm-2 eV-1. However, after annealing above 400 °C, EFs moves back closer to midgap with an increase of Ds. The experimental results are found to obey the barrier height theory of Cowley and Sze.

Effect of low-temperature treatment and subsequent high-temperature annealing on the critical current density of YBa2Cu3O y

The field dependences of the critical current density of the HTSC compound YBa2Cu3O y recovered at T = 920–950°C after the low-temperature treatment have been investigated. At T = 200°C, structural defects are formed in a wet environment, which are capable of initiating pinning of magnetic vortices. A short-term (1–3 h) recovery annealing performed at T = 930–950°C leaves in the samples a fairly large amount of structural defects formed during the low-temperature treatment, which results in a substantial increase in the critical current density in magnetic fields of ∼2 T as compared to the ceramics not subjected to double annealing. A longer high-temperature treatment removes the structural defects formed and brings the electrophysical properties of YBa2Cu3O y to the level characteristic of the ceramics produced by standard technology.

Effect of low-temperature annealing on spectrum FMR in a granulated nanostructure

The effect of low-temperature annealing on the homogeneous FMR spectrum of a granulated (CoFeB) + (SiO2) nanostructure is investigated experimentally. The observed concentration dependence of monoaxial anisotropy fields and shift in the resonance fields before and after annealing are explained within the model of an effective environment.

Effects of low-temperature ozone annealing on operation characteristics of amorphous In–Ga–Zn–O thin-film transistors

Effects of low-temperature annealing were examined for amorphous In–Ga–Zn–O (a-IGZO) thin-film transistors (TFTs). In a previous study, we reported that O2 annealing is effective to improve performances of a-IGZO TFTs when annealed at ≥300°C, but causes large negative threshold voltage shift when annealed at ≤ 200°C. Here, we examined effects of ozone (O3) annealing on physical properties and TFT characteristics of a-IGZO in comparison with conventional O2 annealing. We found little differences in chemical composition, band gap and photoemission spectra between the O2 and the O3 annealed films. On the other hand, free electron density was suppressed well by the O3 annealing even at low temperatures ≤200°C. Moreover, even at 150°C, the TFTs characteristics were improved to the subthreshold voltage swing of 217mV/decade, the saturation mobility of ~11.4cm2(Vs)−1 and the threshold voltage of 0.1V by the O3 annealing. It was also found that the effects of the O3 annealing is more effective for thicker channel TFTs, which would be due to stronger oxidation power and the larger diffusion constant of oxygen atoms produced from O3 molecules than those of O2. These results substantiate that the O3 annealing is more effective to improve TFT characteristics in particular for low-temperature processes at ≤200°C.

Effects of pre-deformation and subsequent low-temperature annealing on transformation, mechanical properties and shape memory behavior of a Ti-rich TiNi alloy

Effects of pre-deformation in the martensitic state and subsequent low-temperature annealing on the phase transformation, tensile properties and shape memory performance of a Ti-49.8 at.% Ni alloy were investigated in order to improve mechanical and memory properties of the alloy. The results show that water quenching from 850 degrees C and subsequent annealing do not induce Ti-rich precipitates in the alloy. Transformation from parent to R-phase appears on cooling for alloys annealed at 350-500 degrees C after pre-deformed to the strain of as high as 19.0%, and the transformation temperature and rate from parent to R-phase are not affected by pre-deformation, but M(s) and M(f) reduce with increasing pre-deformation strain, and the volume fraction of R-phase increases in the microstructure of alloys annealed at low temperature after pre-deformation to higher strain. Tensile and memory properties of the Ti-49.8 at.% Ni alloy can be improved by appropriate pre-deformation (more than 27.8% strain) in the martensitic state and subsequent low-temperature annealing (at 400 degrees C).

Transformation plasticity and shape memory effects in TiNi alloy after low-temperature treatment

The effect of low-temperature annealing on the structure, kinetics of martensitic transformations, and functional properties of an equiatomic TiNi shape memory alloy is studied. Low-temperature annealing of the TiNi alloy is shown to decrease the temperature of the end of the forward martensite transformation Mf and the temperature of the onset of the reverse transformation As, which increases the transformation temperature range. As a result, the shape memory effect is improved due to a decrease in the irreversible strain. These phenomena are assumed to be caused by the hardening of the TiNi alloy induced by low-temperature annealing.

Effect of low-temperature annealing on light-emitting properties of na-Si/SiOx porous nanocomposite films

The effect of low-temperature annealing on light emitting properties of naSi/SiOx porous column-like nanocomposite films has been studied. Influence of type of chemically active gas or inert ambient on PL characteristics is shown. Existence of metastable defects in such structures is shown. A temperature interval for healing the metastable defects is defined. Mechanisms to reduce a non-radiative recombination channel depending on the gas ambient are proposed.

Tuning martensitic transformation and magnetoresistance effect by low temperature annealing in Ni45Co5Mn36.6In13.4 alloys

We studied the influence of post-annealing on magnetic and transport properties in Ni45Co5Mn36.6In13.4 alloys. Our results demonstrate that post-annealing at low temperatures, ⩽300 °C, can lead to a significant change in magnetic properties, martensitic temperature (TM) and magnetoresistance effect through structure relaxations and possible change in atomic order. It was found that TM shifts from 314 to 283 K but the strong metamagnetic behaviour is still retained when the sample is annealed at 300 °C for 3 h. Thereupon, a large magnetoresistance effect over an extended temperature range can be achieved through controlling the heat treatment conditions. Meanwhile, the thermal stability of the novel composition is also disclosed through the investigations on low temperature annealing effect.

Effect of severe plastic deformation on the formation of the nanocrystalline structure and the aging of the multicomponent aluminum-lithium alloy with small additions of Sc and Mg

Effect of severe plastic deformation and subsequent low-temperature annealing on the structural and phase transformations, which are realized in the alloy 1450 on the base of the Al-Li-Cu-Zr system with additives of Sc and Mg has been studied by electron microscopy. The possibility of obtaining a nanocrystalline recrystallized structure in the alloy investigated has been established. It has been shown that its uniformity and dispersiveness depend on the degree of deformation and on the regime of annealing and are determined by the density distribution of particles that are precipitated upon the decomposition of the supersaturated solid solution. The transition of the alloy from microcrystalline to submicrocrystalline or nanocrystalline state changes its phase composition, morphology, and mechanism of nucleation of the precipitated phases and makes it possible to minimize structural factors that exert negative effect on the alloy plasticity.

Photoelectrochemical Characterization of Nanocrystalline Thin-Film Cu2ZnSnS4 Photocathodes

Cu₂ZnSnS₄ (CZTS) nanocrystals, synthesized by a hot injection solution method, have been fabricated into thin films by dip-casting onto fluorine doped tin oxide (FTO) substrates. The photoresponse of the CZTS nanocrystal films was evaluated using absorbance measurements along with photoelectrochemical methods in aqueous electrolytes. Photoelectrochemical characterization revealed a p-type photoresponse when the films were illuminated in an aqueous Eu(3+) redox electrolyte. The effects of CZTS stoichiometry, film thickness, and low-temperature annealing on the photocurrents from front and back illumination suggest that the minority carrier diffusion and recombination at the back contact (via reaction of photogenerated holes with Eu(2+) produced from photoreduction by minority carriers) are the main loss mechanisms in the cell. Low-temperature annealing resulted in significant increases in the photocurrents for films made from both Zn-rich and stoichiometric CZTS nanocrystals.

Effects of low-temperature annealing on polycrystalline silicon for solar cells

The polycrystalline silicon material grown by the edge-defined film-fed growth technique, and often used in solar cell production, is known to be carbon and dislocation rich. Aim of this work was to explore the effect of low-temperature annealing in vacuum on properties of these structural defects, often present in different solar-grade materials. Electrical measurements by deep level transient spectroscopy revealed the presence of the defects typically found in dislocated silicon. Detailed analysis further suggested that they are also carbon related, exhibiting quite unexpected behavior at such low-temperature annealing. Moreover, photoluminescence results showed electron–hole droplet condensation at dislocations after such low-temperature annealing. This further supports the hypothesis that point defects are incorporated at dislocation cores rather than in a cloud at its proximity.

Effect of the atmosphere of low-temperature annealing on the structure and electrophysical properties of nonstoichiometric YBa2Cu3O7 − δ ceramics

The fine structure and electrophysical properties of nonstoichiometric YBa2Cu3O7 − δ ceramics and the effect of low-temperature annealing (t ⩾ 200°C) in various atmospheres on these parameters have been studied. It has been shown that, during annealing in a vacuum, the decomposition is quite sluggish; structures typical of initial stages of decomposition are observed. The decomposition in an inert-gas atmosphere occurs more actively, and structures typical of stages of deep decomposition are realized. It has been found that, during low-temperature annealing, the structure and properties are affected by two factors; these are the decomposition into phases differing in the oxygen content, and water absorption, leading to the transformation with the formation of a pseudo-cubic lattice. The annealing atmosphere substantially affects the kinetics of both processes.