Post-deposition annealing temperature plays an important role in the performance of many photodetectors. In this study, we investigated the effect of annealing on the ultraviolet (UV) detection properties of a visible-blind p-poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/n-SnO2 heterojunction device after exposure to various temperatures ranging from 60 to 210 °C. Our results indicate that the signal-to-noise ratio, responsivity, external quantum efficiency, and specific detectivity of the device initially increase with annealing temperature up to 150 °C and thereafter decrease with further increase in temperature. At −6.0 V reversed bias, the device exposed to 150 °C produce the optimum responsivity of 90.02 ± 1.68 mA W−1, quantum efficiency of (30.58 ± 0.57)%, and detectivity of (3.09 ± 0.19) × 108 Jones. Furthermore, the optimized device at −6.0 V exhibited a rapid rise time of 97.45 ms and a fall time of 98.81 ms. The study highlights the improvement in UV sensing performance of the p-PEDOT:PSS/n-SnO2 heterojunction device on annealing at 150 °C.
In advanced semiconductor manufacturing, precise control of micro-nano structures via plasma etching is crucial. However, physical simulations are computationally intensive and struggle with rate coefficient determination. While data-driven deep learning offers an alternative, existing methods often suffer from blurry profiles, cumulative errors, and poor modeling of complex patterns. To address these challenges, we propose an edge-extended Long Short-Term Memory network (exLSTM) for etching profile evolution prediction. This model integrates a gradient difference loss term with an Extended LSTM architecture, combining the exponential gating of scalar LSTM for long-term dependencies and the matrix memory of matrix LSTM for complex spatial modeling. The model inputs initial profile images and process parameters to generate temporal evolution sequences. Experimental results demonstrate that exLSTM significantly outperforms the baseline Convolutional LSTM. Specifically, for isolated, dense, and Static Random-Access Memory patterns, the model enhances profile clarity and error suppression, achieving Structural Similarity Index Measure values of 0.9855, 0.9720, and 0.9541 at the 20th frame, i.e., the terminal etching profile at 60 s in a sequence sampled at 3 s intervals, respectively. Furthermore, the model generates full sequences in under 0.015 s on a single Graphics Processing Unit, offering a rapid, high-precision tool for process optimization in advanced node manufacturing.
Trace amounts of oxygen and hydrogen can strongly influence the formation of negative carbon ions during focused ion beam–secondary ion mass spectrometry (SIMS) analysis of graphite. In this study, the sputtering behavior of graphite and the detection of single and clustered carbon ions were investigated under systematically varied measurement conditions. Experiments were performed by varying the primary ion current and the analysis field size, enabling a systematic evaluation of ion dose effects. A linear relationship between sputter rate and ion dose was observed. The sputter yield increases at low ion doses and stabilizes at approximately 1.6 C atoms/Ga+ ion for ion doses above 15 nC/μm2. Large analysis fields lead to a decrease in sputter yield accompanied by increased scatter, indicating the onset of sample swelling. Signal stability strongly depends on ion dose. At high ion doses, stable sputtering conditions are reached within about 1 min, whereas up to 20 min are required at low ion doses. Under stable conditions, mass spectral peak heights correspond well with constant signal levels observed in multiple ion detection profiles. Carbon ion intensities vary strongly with measurement parameters but become stable when normalized to simultaneously detected oxygen, hydrogen, or hydroxide signals. These results indicate that trace surface impurities modify the electronic structure of graphite and significantly affect negative ion formation. The findings highlight the importance of surface chemistry for the interpretation of SIMS measurements, particularly in the analysis of graphite-based lithium-ion battery materials.
Over the past several decades, there has been increasing interest in sensory systems based on the surface plasmon resonance (SPR) phenomenon for applications in biotechnology, medicine, and veterinary science. The study provides a comprehensive analysis of modern SPR sensor configurations, classified by modulation types and detection methods. The influence of substrate materials on sensor sensitivity was considered. The potential of polymer chips (PDMS, PMMA) for the disposable and portable sensors was explored. Particular attention was paid to SPR imaging methods and polarization contrast systems. The advancement of SPR imaging methods opens new frontiers for fundamental biology, drug screening, and medical diagnostics by providing spatial and mechanical resolution of complex molecular processes. The application of SPR technologies in medicine and veterinary science was systematized. Particular attention was given to the PLASMON series instruments developed at the V.E. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine in last decades. Their evolution from single-channel prototypes based on the Kretschmann configuration to modern multichannel systems with differential measurement modes, ensuring precise real-time extraction of optical parameters, was addressed. The integration of PLASMON devices with cutting-edge nanotechnology and imaging techniques in next-generation universal diagnostic platforms was discussed.
Pump-down pressure-time data are routinely fitted to infer the surface physics of adsorption, yet models built on different assumptions produce near-indistinguishable fits, so the inferred physics can be an artifact of the fitting choice rather than a property of the surface. This work provides two tools to close that gap: a model-selection criterion suited to autocorrelated pump-down data (a corrected Akaike information criterion with a generalized-least-squares first-order autocorrelation correction, AICc(GLS)), and an identifiability diagnostic that determines whether a given experimental protocol can constrain an adsorption isotherm at all. Applying both to 20 datasets from AISI 1020 low-carbon steel and 316L stainless steel chambers, under three protocols (isothermal pump-down, nonisothermal throughput with a bake, and N-2 vent/repump at 25 degrees C), shows that the protocol, the combination of thermal regime, pumping speed, and surface-area-to-pump-speed (A/S-0) ratio, is the primary factor controlling identifiability. Only the isothermal, high-pumping-speed protocol resolves the isotherm; even there the five candidates fit statistically indistinguishably (all R-2 >= 0.96), so goodness-of-fit cannot select among them and the apparent preference reduces to parsimony under the information criterion: the two-parameter Dubinin-Radushkevich model on most datasets, with the single-energy Langmuir model most parsimonious at 75 degrees C. The chamber-bake protocol is confounded by the thermal ramp and the N-2-vent protocol by the H-2 background, leaving the isotherm unidentifiable in both. The diagnostic identifies when isotherm parameters from pump-down data are physically meaningful rather than fitting artifacts.
We report mercury-probe measurement of the carrier mobility in the two-dimensional electron gas (2DEG) of the epi-structure for GaN-based high electron mobility transistors (HEMTs). This nondestructive method requires no contact metal deposition. The mobility is extracted from the dielectric relaxation frequency of the 2DEG moderated by the barrier layer of the HEMT epi-structure, which is manifested as the inflection frequency of the gate capacitance versus frequency curve. We define the sheet capacitance as the in-plane capacitance of a square thin film to elucidate 2DEG’s large dielectric relaxation frequency and HEMT’s superior high-frequency performance.
At very-low-primary-energy regime, secondary-electron emission enters a regime where classical bulk-transport models break down, and emission becomes governed by quantum surface physics. The incident electron wavelength approaches interatomic distances, elastic scattering dominates over inelastic losses, and the surface potential barrier controls both injection and escape. This review synthesizes the physical mechanisms, material-dependent behavior, and advanced experimental techniques that define this very-low-primary-energy regime. We show how electronic band structure, surface states, work function, and electron affinity collectively determine emission yields and energy distributions across metals, semiconductors, insulators, and two-dimensional materials. The limitations of conventional three-step models are analyzed, and quantum-mechanical frameworks, including dielectric response theory and one-step coherent emission models, are presented as necessary alternatives. Finally, we discuss how understanding very-low-primary-energy secondary-electron emission enables rational surface engineering for applications in electron microscopy, spacecraft charging mitigation, and high-frequency accelerator technologies.
This work presents a systematic investigation of Hf-doped indium-zinc oxide (IHZO) field-effect transistors to elucidate the effects of Hf incorporation on electrical performance and bias stress stability. Owing to the strong oxygen bonding capability of Hf, oxygen vacancy-related carrier generation in the channel is effectively suppressed, resulting in a positive shift in threshold voltage and a gradual reduction in field-effect mobility with increasing Hf doping concentration. By optimizing the doping level, the IHZO device achieves a favorable balance between threshold voltage and mobility, exhibiting excellent overall electrical characteristics. To further enhance electrostatic control over the channel, a dual-gate device architecture was implemented. At a channel length of 100 nm, the dual-gate IHZO transistor demonstrates superior short-channel performance, delivering a high on-state current of 386 μA/μm, a threshold voltage of +0.09 V, and a near-ideal subthreshold swing of 61 mV/dec. Bias stress measurements conducted at a high electric field of 4 MV/cm for 3600 s reveal an extremely small threshold voltage shift of only 0.01 V under positive bias stress, indicating outstanding electrical stability. Compared with previously reported short-channel oxide transistors based on different doping systems, the IHZO devices developed in this work exhibit competitive advantages in mobility, subthreshold characteristics, drive current, and bias stress reliability. These results demonstrate the potential of atomic layer deposition-enabled Hf-doped InZnO as a compelling channel material candidate for advanced nanoscale oxide electronic applications.
This work investigated the deposition of titanium nitride (TiN) films on SAE 1080 steel using the cathodic cage plasma deposition (CCPD) technique. The innovation of this study lies in the evaluation of the simultaneous duplex process (thermochemical diffusion and hard film deposition in a single step) and in the direct influence of electrical potentials (cathodic and floating) and temperatures (400 and 450 °C) on the tribological performance of the steel. The samples were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy, microhardness, Rockwell C adhesion, and microabrasive wear tests. The XRD results confirmed the efficient formation of the hard structural phases Fe2N, Fe4N, and Ti2N. SEM analysis quantified disparities in surface morphology: Treatment at cathodic potential generated significantly thicker films of 6.366 ± 0.75 μm (400 °C) and 5.193 ± 0.45 μm (450 °C), though less uniform due to the edge effect. In contrast, the floating potential produced highly homogeneous films with grain refinement, but with reduced thicknesses of 1.727 ± 0.27 and 1.113 ± 0.14 μm at respective temperatures. In the mechanical tests, the samples at cathodic potential showed the largest increases in surface microhardness, reaching 748.54 ± 93.21 HV (400 °C) and 831.28 ± 87.2 HV (450 °C) compared to 245.63 ± 28.25 HV for the base material, a benefit attributed to the formation of a nitrogen diffusion zone underlying the film. All conditions demonstrated excellent adhesion quality (HF1 level). In the tribological tests under an 8 N load, the property gradient of the cathodic potential ensured the lowest rates and accumulated volumes of microabrasive wear. However, the films generated at floating potential exhibited wear resistance lower than that of the base material, resulting from the fragmentation of the deposited film that generated abrasive debris in the tribo-contact. The coefficient of friction remained below 0.8 for all conditions, with the lowest value recorded for the DP400F sample. It is concluded that the CCPD technique is viable for surface modification of SAE 1080 steel, with the cathodic potential configuration being the most efficient for applications requiring high hardness and wear resistance.
Glass is emerging as the next generation substrate for advanced packaging but adoption is limited because of numerous hurdles such as adhesion of metal lines, stress management, and unavailability of long-term reliability data on glass. The use of liners between copper and glass in through-glass vias (TGVs) is important to manage their coefficient of thermal expansion mismatch, stress-induced cracking, and overall reliability. Critical to understanding liner performance is characterizing the liner’s thickness throughout the TGV. Here, we investigate various nondestructive imaging techniques to determine which may be sufficient for this analysis. For model systems of study, both organic and inorganic liner materials (Parylene C and Parylene C + AZO) are deposited inside 100-μm-diameter TGVs. Both x-ray microcomputed tomography (micro-CT) and two-photon imaging (TPI) are compared to destructive cross-sectional microscopy to assess their appropriateness for liner characterization. Micro-CT is able to detect the liner and measure a thickness comparable to cross-sectional microscopy; however, the resolution of this image is poor and includes much uncertainty. TPI is also able to detect the liner (when liner material is fluorescent) and measure a thickness comparable to cross-sectional microscopy. TPI can also provide thickness measurements throughout the entire length of the TGV, making it a powerful nondestructive technique for assessing liner quality.
Voltage-tunable Josephson junctions (VT-JJs) are an emerging element in superconducting quantum electronics with potential to expand the functionality of conventional designs. While VT-JJs are largely compatible with wafer-scale semiconductor processing, their integration into quantum circuits remains a challenge due to unmitigated semiconductor microwave loss. Here, a deep mesa etch process, wherein the epitaxial material is removed except the VT-JJ device, will facilitate the integration of VT-JJs with low-microwave-loss circuit elements by allowing these circuit elements to be placed directly on a low-loss substrate. A Germanium quantum well is grown by Molecular Beam Epitaxy (MBE) on a float zone silicon substrate with in-situ deposited aluminum contacts. This combination allows the formation of an oxide-free superconductor-semiconductor interface. The deep mesa etch process is optimized to produce a sidewall taper sufficient for continuous metal deposition from the substrate to the top of the mesa for electrostatic gate electrodes and interconnects. The fabricated Josephson junctions demonstrate gate-tunable supercurrents with a maximum critical current over 100 nA and critical-current normal-resistance product of 8.63 μV. These results demonstrate a pathway toward improved integration of voltage-tunable superconducting circuit elements with quantum electronic building blocks such as couplers and qubits.
TiAlN coatings with different modulation ratios were prepared on 42CrMo4 steel by hybrid multiarc ion plating and high-power impulse magnetron sputtering (HiPIMS). As the HiPIMS fraction increased, the coating surface showed fewer macroparticle-related defects and the cross-sectional structure became more uniform and compact. XRD analysis indicated that all coatings were mainly composed of face-centered cubic (Ti,Al)N with a weak AlN peak, while a slight shift of the (111) peak and an increase in the (200) reflection suggested a modulation-ratio-dependent evolution in texture and structural state. Among the alternating coatings, the critical load (LC2) increased from 22 to 47 N and the wear rate decreased from 4.95 & times; 10(-4) to 2.60 & times; 10(-4) mu m(3)& sdot;(N mu m)(-1) as the modulation ratio increased from 1:0.5 to 1:2. Electrochemical tests showed that the 1:2 coating exhibited the lowest corrosion current density, the highest polarization resistance, and the largest capacitive arc radius, indicating the best overall corrosion resistance among the alternating coatings. Overall, increasing the HiPIMS contribution effectively improved the comprehensive performance of the alternating TiAlN coatings.
This study introduces a novel two-step approach for fabricating high-performance transparent conducting films. The method involves depositing a highly conductive flat indium tin oxide (ITO) base layer via magnetron sputtering under conventional conditions, followed by a top layer of ITO nanowires deposited by magnetron sputtering without oxygen in the process gas. We demonstrate that this architecture synergistically combines the low sheet resistance of the dense base layer with the antireflective properties of the nanowire layer, resulting in enhanced light transmittance. Crucially, the predeposited ITO layer significantly facilitates nanowire nucleation, enabling their growth at reduced temperatures compared to direct deposition on bare glass. Sputtering on bare glass and ITO-precoated substrates at temperatures ranging from 200 to 550 degrees C was used to elucidate substrate- and temperature-dependent growth mechanisms. Energy-dispersive x-ray mapping demonstrated substrate-dependent tin depletion in nanowire bodies and pronounced tin segregation at nanowire tips, governed by diffusion dynamics. Furthermore, the nanostructured surface imparts tunable wettability, transitioning from hydrophilic on bare glass to highly hydrophobic, with contact angles as high as
Achieving and maintaining ultraclean vacuum environments is critical for contamination-sensitive processes such as semiconductor manufacturing, where residual gases directly affect performance and reproducibility. During pump-down, H2O outgassing from ambient-exposed technical materials often dominates the gas load, yet energetics-resolved studies of H2O release from these materials remain limited compared with ideal, single-crystal surfaces. In this work, ultrahigh-vacuum temperature-programmed desorption (TPD) was used to investigate H2O outgassing from Mo, 304 stainless steel, 6061 aluminum, Macor, and Si3N4 following exposure to 50% relative humidity (RH) at 20 degrees C. TPD spectra quantified retained H2O and enabled the extraction of apparent desorption-energy distributions. Coupling these distributions to a surface "sojourn-time" model translated TPD-derived energetics into effective release timescales, identifying which energetic states dominate gas load at a given temperature and how elevated bakeout temperatures accelerate H2O desorption. Molybdenum desorbed 1.5-3.7 monolayer equivalents of H2O over a broad range (similar to 50-650 degrees C) for exposure times from 15 min to 480 h with recurring desorption features embedded within a broad similar to 90-260 kJ/mol apparent desorption-energy envelope. X-ray and ultraviolet photoelectron spectroscopy measurements showed that ambient exposure forms a hydroxylated, MoO3-rich surface that progressively dehydrates and reduces to a metallic state during heating. Applying the same protocol to other materials revealed strongly material-dependent H2O retention. After 20 h at 50% RH, Mo, 304 SS, and Si3N4 released similar to 1-3 monolayers of H2O, whereas 6061 aluminum and Macor released substantially larger amounts at lower temperatures (<200 degrees C). These measured inventories and desorption-energy distributions provide a quantitative basis for comparing vacuum materials and optimizing pump-down and bakeout strategies.
CoFeB is a critical ferromagnetic material in magnetic tunnel junctions (MTJs), the fundamental components of magnetic random access memory (MRAM) devices. The precise control of CoFeB’s etching behavior is essential for optimizing MTJ performance. In this study, the etching characteristics of CoFeB magnetic nanofilms were examined using an inductively coupled plasma reactive ion etching (ICP-RIE) system with Ar, CO/Ar, and SF6/Ar plasmas. AR-N photoresist was employed as the etching mask to investigate the effects of ICP power, radio frequency (RF) bias power, and chamber pressure on both the etching rate and the resulting morphology. Our findings demonstrate that effective etching of CoFeB can be achieved using pure Ar plasma. Additionally, optimizing power and pressure parameters improves the etching selectivity between the CoFeB nanofilm and the photoresist. However, after physical etching with pure Ar, significant redeposition was observed, leading to an increase in the nanopillar diameter. The introduction of CO or SF6 into the Ar plasma resulted in a marked reduction in the etching rate of CoFeB. Additionally, etching experiments conducted on different overlayer-substrate thin film combinations revealed notable differences in both etching rates and morphology.
In advanced semiconductor manufacturing, achieving ultrahigh ashing uniformity is critical. This study systematically investigated the combined effects of the total gas flow rate and nitrogen addition in an inductively coupled plasma ashing process. A two-dimensional axisymmetric fluid model was integrated with experimental diagnostics. The results revealed that within a flow rate range of 200-1000 SCCM, the expanding separation vortex and enhanced convective transport synergistically homogenized the spatial distribution of reactive species, resulting in uniform ashing across the wafer. Furthermore, the performance improvement observed with the 10% N-2 addition is primarily driven by the "NO poisoning," which suppresses O atom loss at the surface through a marked significance in the sticking coefficient. This mechanism effectively resolves the conventional trade-off between the ashing rate and uniformity. An optimized process window of 500-1000 SCCM with 10% N-2 consistently delivered a high ashing rate (>500 nm/min) and excellent within-wafer uniformity (<3%).
Silicon nanowire field emitters were fabricated on top of microtubes on a silicon chip (dimensions including contact pads: 8 & times; 8 mm). There are 2437 microtubes (diameter: 8 mu m, height: 30 mu m, spacing: 40 mu m) in the array over an area of 3.38 mm(2). A process was developed to create an integrated metal gate for the extraction electrode. This involved coating the emitters with a uniform benzocyclobutene layer and fabricating a titanium/nickel extraction gate using lift-off. A plasma etching process was used to selectively remove the benzocyclobutene anisotropically around the microtubes, ensuring the preservation of the emitters and the extraction gate. The design reduces the capacitance between the cathode and gate and maximizes the length of the leakage paths between the cathode and gate. This reduces the overall risk of discharges between the two electrodes as well as the energy stored in the system for a given extraction voltage. The electron sources demonstrated transmission rates exceeding 96%, with currents reaching 0.4 mA at extraction voltages of 250 V for several hours under voltage-controlled operation. Investigations after the measurements showed that isolated discharges destroyed individual emitters during operation, but the electron sources remained functional. Consequently, these cathodes demonstrated resilience to failure caused by discharge-related damage due to the low capacity of the system. At higher voltages (300 V) and currents (2 mA); however, these samples exhibited catastrophic arcing, as at these voltages, the energy stored in the capacitance was large enough to result in the destruction of larger areas of the arrays and the formation of conductive paths between the cathode and the gate.
We introduce the new simulation tool ContaminationFlow, a test-particle Monte-Carlo (TPMC) simulator to predict the spread of contamination in vacuum environments with a view to virtual prototyping of space vehicles and earth bound vacuum applications. The paper comprises a description of the TPMC method for transient particle transport simulations under molecular flow conditions and for long-term investigations up to several years, which is illustrated by a benchmark problem. The implemented physical models are described along with the simulation algorithm. Strengths and weaknesses of the software are evaluated as well as future measures with regard to the improvement of the prediction accuracy are pointed out.
Failure analysis is essential for semiconductor technology development, manufacturing yield improvement, and long-term product reliability. As device dimensions continue to shrink into the single-digit nanometer regime, traditional optics-based global fault isolation (GFI) techniques—such as lock-in thermography, photon emission microscopy, optical beam-induced resistance change, thermally induced voltage alteration, critical parameter analysis, and laser voltage imaging/probing—are increasingly limited by the diffraction limit of light and can no longer precisely localize defects in dense 3D structures, including FinFETs and gate-all-around (GAA) nanosheet devices. Consequently, semiconductor failure analysis now relies heavily on SEM-based local fault isolation techniques, including nanoprobing, active voltage contrast, electron beam absorption current, electron beam induced current, and electron beam induced resistance change, which offer true nanoscale spatial resolution. However, these SEM-based techniques are only suitable to investigate a small area, which need be priorly narrowed down by GFI. This article evaluates the strengths and limitations of both optics-based and SEM-based techniques and presents case studies showing how combining these complementary techniques enables faster, more efficient, and more accurate defect localization in advanced 2 nm GAA nanosheet devices.
