- 标题
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- 实验方案
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Focused Ion Beam
摘要： Hybrid superconducting-spin systems offer the potential to combine highly coherent atomic quantum systems with the scalability of superconducting circuits. To fully exploit this potential requires a high-quality-factor microwave resonator, tunable in frequency and able to operate at magnetic fields optimal for the spin system. Such magnetic fields typically rule out conventional Al-based Josephson-junction devices that have previously been used for tunable high-Q microwave resonators. The larger critical field of Nb allows microwave resonators with large field resilience to be fabricated. Here we demonstrate how constriction-type weak links, patterned in parallel into the central conductor of a Nb coplanar resonator with a neon focused ion beam, can be used to implement a frequency-tunable resonator. We study transmission through two such devices and show how they realize high-quality-factor, tunable, field-resilient devices that hold promise for future applications coupling to spin systems.
关键词： magnetic field resilience,focused ion beam,superconducting,tunable resonator,Nb,nano-SQUID
更新于2025-09-23 15:23:52
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Effect of short-circuit stress on the degradation of the SiO2 dielectric in SiC power MOSFETs
摘要： This paper presents the impact of a short-circuit event on the gate reliability in planar SiC MOSFETs, which becomes more critical with increased junction temperature and higher bias voltages. The electrical waveforms indicate that a gate degradation mechanism takes place, showing a large gate leakage current that increases as the gate degrades more and more. A failure analysis has been performed on the degraded SiC MOSFET and then compared to the structure of a new device to identify possible defects/abnormalities. A Focused-Ion Beam cut is performed showing a number of differences in comparison to the new device: (i) cracks between the poly-silicon gate and aluminium source, (ii) metal particles near the source contact, and (iii) alterations in the top surface of the aluminium source. The defects have been correlated with the increase in gate-leakage current and drain-leakage current.
关键词： Focused-Ion Beam,Short circuit,Gate-oxide breakdown,Gate oxide,Degradation,Defects,Reliability,SiC MOSFET,Failure analysis,SEM
更新于2025-09-23 15:22:29
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Voids in Kesterites and the Influence of Lamellae Preparation by Focused Ion Beam for Transmission Electron Microscopy Analyses
摘要： Kesterite solar cells based on Cu2 ZnSnS4 and Cu2 ZnSnSe4 (CZTSe) are potential future candidates to be used in thin-film solar cells. The technology still has to be developed to a great extent and for this to happen, high levels of confidence in the characterization methods are required, so that improvements can be made on solid interpretations. In this study, we show that the interpretations of one of the most used characterization techniques in kesterites, scanning transmission electron microscopy (STEM), might be affected by its specimen preparation when using focused ion beam (FIB). Using complementary measurements based on scanning electron microscopy and Raman scattering spectroscopy, compelling evidence shows that secondary phases of ZnSe mixed in the bulk of CZTSe are the likely cause of the appearance of voids in STEM lamellae. Sputtering simulations support this interpretation by showing that Zn in a ZnSe matrix is preferentially sputtered compared with any metal atom in a CZTSe matrix.
关键词： Cu2 ZnSn(S, Se)4 (CZTSSe),thin-film solar cells,transmission electron microscopy (TEM),focused ion beam (FIB),kesterite
更新于2025-09-23 15:22:29
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Influence of ion species of AuSi liquid metal alloy source-focused ion beam on SiO2/Si nanopatterning
摘要： This work investigates the influence of the ion source (Au+ and Si+2 ions) of liquid metal alloy source-focused ion beam on the nanopattering. Two sets of SiO2/Si nanopatterns with a width of 450 nm on Silicon on insulator (SOI) substrate are fabricated by 30 keV Au+ and Si+2 ions, respectively. To study this effect, the sputtering yield is calculated using the volume loss method from atomic force microscopy (AFM) profiles obtained for each set. The results of the sputtering yield were compared with theoretical results calculated from Yamamura model for normal incidence for validation. The comparison showed a good agreement between the two results with a relative difference of about 5.3 % obtained using Si+2 ions.
关键词： Liquid metal alloy source-focused ion beam,Milling,Sputtering yield,Nanopattering
更新于2025-09-23 15:21:01
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Highly Rectifying Heterojunctions Formed by Annealed ZnO Nanorods on GaN Substrates
摘要： We study the effect of thermal annealing on the electrical properties of the nanoscale p-n heterojunctions based on single n-type ZnO nanorods on p-type GaN substrates. The ZnO nanorods are prepared by chemical bath deposition on both plain GaN substrates and on the substrates locally patterned by focused ion beam lithography. Electrical properties of single nanorod heterojunctions are measured with a nanoprobe in the vacuum chamber of a scanning electron microscope. The focused ion beam lithography provides a uniform nucleation of ZnO, which results in a uniform growth of ZnO nanorods. The specific configuration of the interface between the ZnO nanorods and GaN substrate created by the focused ion beam suppresses the surface leakage current and improves the current-voltage characteristics. Further improvement of the electrical characteristics is achieved by annealing of the structures in nitrogen, which limits the defect-mediated leakage current and increases the carrier injection efficiency.
关键词： chemical bath deposition,nanoscale heterojunctions,ZnO nanorods,nanoprobe in the scanning electron microscope,current-voltage characteristics,annealing,focused ion beam patterning
更新于2025-09-23 15:19:57
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Defect Localization and Nanofabrication for Conductive Structures with Voltage Contrast in Helium Ion Microscopy
摘要： As the dimensions of feature sizes in electronic devices decrease to nanoscale, an easy method for failure analysis and evaluation of processing steps is required. Gallium focused ion beam (Ga-FIB) or scanning electron microscope (SEM) are efficient approaches to detect voltage contrast for addressing failure analysis in semiconductor devices and processing. However, Ga-FIB may cause damage or implantation to the surface of the analyzed area, and its resolution is low. Helium ion microscopy (HIM) uses a light ion beam (helium or neon) for imaging and fabrication in nanoscale. With passive voltage contrast (PVC) in HIM images, the defect localization for failure of conductive structures can be rapidly and easily detected with sufficient voltage contrast. Furthermore, a defect gap as narrow as sub 10-nm can be investigated with HIM imaging. PVC with HIM is an efficient method for defect localization at nanoscale with minimal damage to the analyzed area. For circuit edit and failure analysis, it may be necessary to intentionally cut the conductive connection. In this circumstance, final results can be easily verified using PVC imaging with HIM. With XeF2 gas assistance, both helium and neon ion beams can be used to perform nanofabrication for metal disconnection. XeF2 gas plays an important role in preventing deposition of conductive materials on etching region and enhancing material removal rates to achieve electrically isolated structures. The etching rate with a neon ion beam is much faster than that of a helium ion beam. PVC in HIM images with controllable operation and dimensions using a helium ion beam with XeF2 gas assistance could also be used to localize a hidden defect for a single-location-defect situation. With neon ion beam irradiation on a defective location, PVC can be used to find the defect locations in the case of a series of defects.
关键词： defect,voltage contrast,XeF2,focused ion beam,etching,helium ion microscopy,nanofabrication
更新于2025-09-19 17:15:36
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Precise Potential Observation of a Biased GaAs p-n Junction by <i>in situ</i> Phase-shifting Electron Holography; é????§??°??????GaAs p-n??￥??????é???2??o|é???-??·??????-??°????????￡???????????′è|3?ˉ?;
摘要： 昨今，半導体デバイスの研究開発において，動作中の電位温度 120 K の低温下でバルク試料の一部を薄膜化することにより作製した．この試料を電圧印加用 TEM 試料ホルダーにセットし，外部電源と電気的に接続することで TEM 内試料への電圧印加を可能とした．観察はホログラフィー電子顕微鏡(HF3300EH)を用いて加速電圧 300 kV で実施した．位相シフト法による位相再生には，入射電子線の初期位相をシフトして撮影した50枚のホログラムを用いた．
关键词： pn junction,cooling focused ion beam,electron beam holography
更新于2025-09-19 17:13:59
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Cryo-focused ion beam preparation of perovskite based solar cells for atom probe tomography
摘要： Focused-ion beam lift-out and annular milling is the most common method used for obtaining site specific specimens for atom probe tomography (APT) experiments and transmission electron microscopy. However, one of the main limitations of this technique comes from the structural damage as well as chemical degradation caused by the beam of high-energy ions. These aspects are especially critical in highly-sensitive specimens. In this regard, ion beam milling under cryogenic conditions has been an established technique for damage mitigation. Here, we implement a cryo-focused ion beam approach to prepare specimens for APT measurements from a quadruple cation perovskite-based solar cell device with 19.7% efficiency. As opposed to room temperature FIB milling we found that cryo-milling considerably improved APT results in terms of yield and composition measurement, i.e. halide loss, both related to less defects within the APT specimen. Based on our approach we discuss the prospects of reliable atom probe measurements of perovskite based solar cell materials. An insight into the field evaporation behavior of the organic-inorganic molecules that compose the perovskite material is also given with the aim of expanding the applicability of APT experiments towards nano-characterization of complex organo-metal materials.
关键词： field evaporation,solar cells,APT,atom probe tomography,FIB,cryo-focused ion beam,perovskite,halide loss
更新于2025-09-16 10:30:52
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Ion irradiation of III–V semiconductor surfaces: From self-assembled nanostructures to plasmonic crystals
摘要： Ion-irradiation of semiconductor surfaces has emerged as a promising approach to generate a variety of self-organized nanostructures. Furthermore, the combination of focused-ion-irradiation with molecular-beam epitaxy provides unprecedented design and control of surfaces and interfaces of hybrid materials at the atomic level during fabrication. In this review, we describe the directed self-assembly of nanostructure arrays ranging from islands to nanorods to 3-dimensional nanoparticle (NP) arrays. First, we discuss focused-ion-irradiation of III–V surfaces, which leads to preferential sputtering of group V species, followed by the formation of group III-rich metallic nanostructures. For continued irradiation beyond a threshold dose, the nanoparticle (NP) evolution is determined by the sputtering yield and the local ion beam angle of incidence, resulting in arrays of nanoparticles, nanorods, or nanoparticle chains. In addition to describing the formation of close-packed embedded Ga:GaAs nanocomposites using overgrowth of focused-ion-beam fabricated NP arrays, we discuss the surface plasmon resonances of NP arrays as well as the influence of both surface and buried NP arrays on the GaAs photoluminescence efficiency. Finally, we discuss the potential of “plasmonic crystals” for plasmon-enhanced optoelectronics.
关键词： self-assembled nanostructures,ion irradiation,plasmonic crystals,molecular-beam epitaxy,III-V semiconductor,nanoparticle arrays,surface plasmon resonances,photoluminescence efficiency,focused-ion-beam
更新于2025-09-12 10:27:22
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Helium focused ion beam direct milling of plasmonic heptamer-arranged nanohole arrays
摘要： We fabricate plasmonic heptamer-arranged nanohole (HNH) arrays by helium (He) focused ion beam (HeFIB) milling, which is a resist-free, maskless, direct-write method. The small He+ beam spot size and high milling resolution achieved by the gas field-ionization source used in our HeFIB allows the milling of high aspect ratio (4:1) nanoscale features in metal, such as HNHs incorporating 15 nm walls of high verticality between holes in a 55-nm-thick gold film. Drifts encountered during the HeFIB milling of large arrays, due to sample stage vibrations or He beam instability, were compensated by a drift correction technique based on in situ He ion imaging of alignment features. Our drift correction technique yielded 20 nm maximum dislocation of HNHs, with 6.9 and 4.6 nm average dislocations along the horizontal and vertical directions, respectively. The measured optical resonance spectra of the fabricated plasmonic HNH arrays are presented to support the fabrication technique. Defects associated with HeFIB milling are also discussed.
关键词： plasmonics,focused ion beam,helium ion microscopy,nanofabrication
更新于2025-09-12 10:27:22