Multilayer Stacked Structures Research Articles

CMP characteristics of IGZO thin film with a variety of process parameters

Recently, amorphous indium gallium zinc oxide (a-IGZO) has been studied in the field of 3D transistors as a channel material for high mobility, good uniformity, and low leakage current performance. The CMP process needs to be applied to fully remove surface IGZO in a multilayer film stack structure and achieve the purpose of planarization. As we all know, the CMP characteristics of the desired removal rate with stability and within-wafer non-uniformity (WIWNU%) play an important role in the CMP process. In this paper, the variation of the removal rate and the non-uniformity for IGZO thin film were studied with various process parameters (such as polishing time, slurry flow rate, slurry dilution, head pressure, head and table speed). The results mean that the removal rate and the non-uniformity of IGZO thin film can be tuned by changing process parameters, which can enhance the confidence about the feasibility of IGZO-CMP in the application of advanced technology.

Advanced Fanout Embedded Bridge Packaging Technology for Chiplets Integration

The increasing amount of data from all sectors driven by digital transformation is raising a problem of operational and storing cost of the data. Meanwhile, the exponential cost leaps of silicon scaling, the unfordable increasing of Si die size over reticle limit and unsustainable computer energy exceeding the world’s energy production have created an inflection point for semiconductor industry. It has driven the development of More-Than-Moore to augment increased device and system performance. Chiplets integration provides more flexible mix-and-match systems to accelerate performance and power efficiency. It is driving the development of advanced packaging technology to enable heterogeneous chiplets integration with separate designs and different manufacturing process nodes within a single package for yield improvement, IP reuse, performance and cost optimization, as well time to market reduction. Several advanced packaging technologies have been developed and used widely to integrate multi-chips with fine line/space interconnections, such as 2.5D Si TSV interposer, Fanout RDL (re-distribution layer) and EMIB (Embedded Multi-die Interconnect Bridge). Different packaging technologies have different sweet spots to fulfill various applications depending on the device design and performance requirements. In ASE, we have developed and introduced FOCoS (FanOut Chip on Substrate) chip first (FOCoS-CF) and FOCoS chip last (FOCoS-CL) technologies by using RDL interconnect for chiplets integration. However, due to the inherent fanout RDL process limitation, it has hit the bottleneck to manufacture RDL with higher layer counts (> 6 layers) and finer Line/Space (L/S < 1um/1um) for the applications that require high density die to die connections, high input/output (I/O) counts and high-speed signal transmitting. In this paper, a new FOCoS technology named as FOCoS embedded Si bridge (FOCoS-B) has been developed for high density die to die interconnect with RDL L/S < 1um/1um chipets integration for HPC application. The FOCoS-B packaging technology enables the USR (Ultra Short Reach) interconnection between die to die by embedded a small Si die in fanout RDL interposer. The small Si die play an interconnection bridge role between chiplets with L/S 0.8um/0.8um. Two FOCoS-B test vehicles (TVs) will be introduced in this study. One TV named as TV-1 is integrated by two chiplets of 1 ASIC die and 1 HBM2e with 1 Si bridge die to form a fanout module, which it is subsequently assembled on a FCBGA package with body size of 40x30mm2. Another TV listed as TV-2 is composed of two identical fanout modules, which are assembled on one FCBGA substrate with body size of 78x70mm2 in MCM (multi-chip-module) arrangement. The fanout module for TV-2 is integrated by 1 ASIC and 4 HBM2e with 4 bridge dies. TV-2 will have total 10 chiplets (2 ASICs and 8 HBM2e with 8 Si bridge dies). The process flow for FOCoS-B will be illuminated. The process DOE and the impact on warpage will be discussed. Furthermore, the reliability validations on two TVs will also be demonstrated. Finally, the comparison on warpage among different FOCoS solutions (FOCoS-B, FOCoS-CL and FOCoS-CL) for chiplets integration have been presented. The results indicated that the material selections and property compatibilities among the multi-layer stacked structures (Si die, RDL, Molding compounds, Underfill) play critical roles in warpage control in FOCoS-B processes. The package warpage of FOCoS-B and FOCoS-CL has showed similar behaviors. FOCoS-CF showed slightly high package warpage than that of FOCoS-B. The results also revealed that FOCoS-B has provided a wide choice and flexibility for multi bridge dies integration successfully for HPC application.

A High-Reliability RF MEMS Metal-Contact Switch Based on Al-Sc Alloy.

This paper presents a new metal-contact RF MEMS switch based on an Al-Sc alloy. The use of an Al-Sc alloy is intended to replace the traditional Au-Au contact, which can greatly improve the hardness of the contact, and thus improve the reliability of the switch. The multi-layer stack structure is adopted to achieve the low switch line resistance and hard contact surface. The polyimide sacrificial layer process is developed and optimized, and the RF switches are fabricated and tested for pull-in voltage, S-parameters, and switching time. The switch shows high isolation of more than 24 dB and a low insertion loss of less than 0.9 dB in the frequency range of 0.1-6 GHz.

Interface thermal resistance of micron-thin film

The utilize of multilayer stacked structure dielectric is very common in electrical engineering, such as thin film capacitor wound by multilayer dielectric, and oil paper cable insulation layer formed by multilayer oil paper winding. Interface thermal resistance between dielectric layers are crucial thermo-physical parameters, which are very important for the thermal management of electric devices to improve the operating stability. However, there are some difficulties in precisely measuring thermal resistance parameters between micron-thin films by conventional ways. In this paper, a novel method is proposed for measuring thermal resistance parameters between films based on the thermal pulse method, which is normally used for mapping space charge or electric field distribution. The sample in this paper is of a multilayer structure containing at least one insulating dielectric film. The parameters of the interface thermal resistance of the multilayer structure are obtained by simulating and analyzing the thermal response current characteristics of the dielectric film. To study the characteristics of interface thermal resistance, several different thin film interfaces were designed by changing the type of thermal interface materials and the roughness of the contact surface. The obtained data of the interface thermal resistance show well consistence with the theoretical expectation.

Helical Trilayer Nanographenes with Tunable Interlayer Overlaps

The synthesis of well-defined nanocarbon multilayers, beyond the bilayer structure, is still a challenging goal. Herein, two trilayer nanographenes were synthesized by covalently linking nanographene layers through helicene bridges. The structural characterization of the trilayer nanographenes revealed a compact trilayer-stacked architecture. The introduction of a furan ring into the helicene linker modulates the interlayer overlap and π-conjugation of the trilayer nanographenes, enabling the tuning of the interlayer coupling, as demonstrated by optical, electrochemical, and theoretical analyses. Both synthesized trilayer nanographenes are rigid chiral nanocarbons and show a chirality transfer from the helicene moiety to the stacked nanographene layers. These helical trilayer nanographenes reported here represent the covalently linked multilayer nanographenes rather than bilayer ones, showing the tunable multilayer stacking structure.

Real-Time UAV Patrol Technology in Orchard Based on the Swin-T YOLOX Lightweight Model

Using unmanned aerial vehicle (UAV) real-time remote sensing to monitor diseased plants or abnormal areas of orchards from a low altitude perspective can greatly improve the efficiency and response speed of the patrol in smart orchards. The purpose of this paper is to realize the intelligence of the UAV terminal and make the UAV patrol orchard in real-time. The existing lightweight object detection algorithms are usually difficult to consider both detection accuracy and processing speed. In this study, a new lightweight model named Swin-T YOLOX, which consists of the advanced detection network YOLOX and the strong backbone Swin Transformer, was proposed. Model layer pruning technology was adopted to prune the multi-layer stacked structure of the Swin Transformer. A variety of data enhancement strategies were conducted to expand the dataset in the model training stage. The lightweight Swin-T YOLOX model was deployed to the embedded platform Jetson Xavier NX to evaluate its detection capability and real-time performance of the UAV patrol mission in the orchard. The research results show that, with the help of TensorRT optimization, the proposed lightweight Swin-T YOLOX network achieved 94.0% accuracy and achieved a detection speed of 40 fps on the embedded platform (Jetson Xavier NX) for patrol orchard missions. Compared to the original YOLOX network, the model accuracy has increased by 1.9%. Compared to the original Swin-T YOLOX, the size of the proposed lightweight Swin-T YOLOX has been reduced to two-thirds, while the model accuracy has slightly increased by 0.7%. At the same time, the detection speed of the model has reached 40 fps, which can be applied to the real-time UAV patrol in the orchard.

Research on Fertility Policy Under the Background of Three-Child Policy

Reasonable analysis and formulate relevant policy to control population stable growth is of great significance to social development and economic development in this paper, combining with the relevant data search conducted fertility policy mathematical modeling and analysis, introduces both short-term and long-term memory neural networks with time characteristics (LSTM), considering the population forecast may be is more sensitive to high-dimensional feature, The multi-layer stacked long and short-term memory neural network (DLSTM) was used as the prediction model, and the multi-layer stacked structure significantly improved the robustness and accuracy of prediction.

Design and verification an all-dielectric metasurface and its thermal properties

All dielectric metasurface is widely used in communication and sensing due to its rich resonance properties. Accurate measurement of thermal resonance properties (such as thermal diffusivity and thermal resistance) of all dielectric metasurface is beneficial for thermal management and extending the service life of functional devices. An all dielectric metasurface with a Si disk array is proposed and verified. The thermal response current of the metasurface sample is measured based on the thermal pulse method and fitted (using the time domain and frequency domain means). The thermal diffusivity and thermal resistance are achived by analyzing the thermal response current. The thermal diffusivity of the metasurface is 8.2, and the thermal resistance is 6.3 (thermal pulse energy is 1.2 mJ, electric field strength 36 kV/mm, with a TIM layer). Four sets of detailed experiments are carried out and measurements indicate that thermal diffusivity and resistance are basically stable: the electric field strength is within 36–54 kV/mm, thermal pulse intensity is in the range of 1.2–1.8 mJ, the thicknesses of the metasurface sample within 4.0μm-5.0μm, and the thicknesses of the standard substrate in the range of 8.0μm-9.5μm. This is beneficial to the thermal management and heat dissipation of functional devices. Moreover, higher thermal response current can be achieved by this proposed metasurface sample than the multilayer stack structure due to more heat pulse energy is absorbed inside of the sample.

Evaluation of Chemical Bonding States in Multilayer Interconnect Structures for Thermal Management in Next Generation Very Large Scale Integration

1. Background and purpose Currently, it is expected that Ru is going to be introduced in place of Cu, which is the mainstream interconnect material in the very large scale integrated (VLSI) circuit. As high integration has been proceeding, the interconnect is expected not only having excellent electrical characteristics and reliability, but also providing an effective pathway for the removal of the heat generated by device operation [1]. The increasing current density in the narrowing interconnect produces Joule heat. The generated heat is removed by a heat sink attached to the substrate through the interconnect. Therefore, if the thermal resistance between the substrate and the interconnect is high, the heat cannot be removed efficiently and the interconnect temperature rises, lead to a degradation of VLSI reliability [2].In this study, we evaluated chemical bonding states of Ru/TaN/(SiOx/)Si stacking structure to clarify the mechanism contributing thermal resistance for the superior thermal management in VLSI. 2. Experimental method A 5 nm TaN was deposited by reactive sputtering (Deposition conditions: 25°C, 300 W, 1.0×10-5 Pa, Ta target) and subsequently 10 nm Ru was deposited by magnetron sputtering on a Si substrate with approximately 2 nm-thick native oxide. We prepared four samples with Ar:N2 gas ratios of 19:1, 17:3, 16:4, and 15:5, respectively, during the TaN deposition. The total thermal resistance was measured by the Frequency Domain Thermoreflectance (FDTR) method under vacuum condition.We also evaluated the chemical bonding states at the interface by Laboratory Hard X-ray Photoelectron Spectroscopy (Lab. HAXPES). The measurement conditions were kinetic energy of 9.25 keV, energy resolution of 0.5 eV, energy step of 50 meV, beam diameter of 50 μm2, and detectable depth of 50 nm, respectively. Au 4f was used as a reference of the energy calibration during for the analysis. 3. Results and Discussion The thermal resistance measured from the entire Ru/TaN/(SiOx/)Si stacking structure was reported by previous studies [1]. It can be seen that the thermal resistance decreases with the increase of N2 flow rate. In order to discuss the mechanism for determination of the thermal conductance, we performed nondestructive measurements by Lab. HAXPES.Figures 1 and 2 show the photoelectron spectra obtained from Ru 3d (Ar:N2=19:1, 15:5) and Si 1s (Ar:N2=19:1, 15:5), respectively. From Fig. 1, no significant change is observed in Ru 3d spectra even within the N2 gas flow rate changes. Therefore, the cause of the change in thermal resistance with the N2 gas flow rate change cannot be found at the Ru/TaN interface. On the other hand, from the Si 1s spectrum shown in Fig. 2, it can be confirmed that the peak intensity due to Si-N or Si-O-N bonds increases with increasing N2 gas flow rate. Therefore, it can be considered that the Si-N or Si-O-N bonds formed at the TaN/(SiOx/)Si interface as the N2 gas flow rate increased promoted heat transport and contributed to the reduction of thermal resistance.In summary, the important mechanism to control the thermal resistance became clear by the non-destructive evaluation of the chemical bonding states in the multilayer stacking structure using Lab. HAXPES. Acknowledgement This work was supported by the CREST under Project No. JPMJCR19Q5 of the Japan Science and Technology Corporation (JST).

Characterization of cosputtered NbTaMoW films

In this study, NbTaMoW medium-entropy alloy films were prepared using a cosputtering apparatus with four sputter guns. Pure-element targets were used for sputtering. The rotational speeds of the substrate holder (RS) were 1–30 rpm. Lower RS values resulted in the formed films exhibiting a multilayer stacked structure with a cyclical gradient concentration. The crystalline phases, mechanical properties, and oxidation behavior of the prepared NbTaMoW films were investigated. The uniformity of the prepared multilayered alloy films increased with the RS value. The monolithic NbTaMoW alloy films prepared at 30 rpm exhibited a single body-centered cubic (BCC) phase, hardness of 12.9 GPa, and Young's modulus of 278 GPa. The BCC phase evolved into a combination of multiple BCC phases when RS was <10 rpm. The multilayered NbTaMoW alloy films prepared at 10 rpm exhibited high hardness of 14.1 GPa and a comparable Young's modulus of 274 GPa. The prepared NbTaMoW films exhibited activation energy of 104 kJ/mol at 350–600 °C in air, and MoO3 was volatilized at temperatures of ≥550 °C. The monolithic and multilayered NbTaMoW films with a thickness of approximately 1240 nm were completely oxidized after annealing at 600 °C for 2 h.

Facile preparation of 3D graphene frameworks as functional modification platform for sensitive electrochemical detection of chloride ions

Multilayer graphene oxide(MGO) highly stacked nature restricts its application in the sensor field, and obtaining high-quality 3D graphene remains a significant challenge. Herein, we report the direct use of MGO to synthesize highly dispersed and rich ordered mesoporous 3D reduced graphene oxide frameworks(rGOFs) through a novel improved KOH activation method, which is based on the pre-treatment process of fully adsorbing and fixing the appropriate amount of K + by using the limited interlayer space of MGO and freeze-drying crystallization technology. Surprisingly, different from previous reports that only the micropores and individual macropores have been obtained by conventional KOH activation, we fully confirmed the dense and ordered mesoporous defects on the surface of rGOFs by SEM for the first time, as well as the multilayer stacked structure of rGOFs is in line with the typical 3D structure. Besides, rGOFs have the excellent properties of reduced graphene oxide (rGO) and a particular 3D framework structure, making it an excellent functionalized modification platform. In order to verify the performance of rGOFs as a framework platform, in which amination modification and small-size Ag NPs loading were successfully realized, the constructed Ag@rGOF-NH 2 /GCE sensor detects chloride ions over a wide linear concentration range of 5 μmol L −1 -10 μmol L −1 , with the detection limit as low as 0.1 μmol L −1 (S/N = 3). This work would not only open a new path to synthesize 3D graphene with excellent performance, and the concept of graphene frameworks nanomaterial is proposed for the first time, but also promotes its excellent performance as an ideal matrix platform for other nanomaterials in the field of electrochemical sensing.

A broadband metamaterial absorber based on multilayer-stacked structure

In this paper, a broadband metamaterial absorber (MA) based on multilayer structure is proposed in the terahertz region. Different from the general multilayer structure, the structure we designed superimposes with different resonators in the “horizontal direction” of the bottom metal plate. The unit of the absorber is composed of several different size metal and dielectric layers which are placed vertically on a metal plate. The numerical results show that the MA has a broadband absorption from 5 THz to 7.75 THz, with the absorption rate larger than 80%. A calculation formula is first given to calculate the absorption frequency, and we compare the simulation results with the calculation results to verify the accuracy of the formula. What is more, the physical mechanism of the perfect absorption can be studied based on the distribution of E-field in the absorber, the standing wave theory, the distribution of energy density and the equivalent impedance theory.

The Optical Constants of Solution‐Processed Semiconductors—New Challenges with Perovskites and Non‐Fullerene Acceptors

AbstractAccurate determination of the optical constants of thin film solids has been an ongoing endeavor in optoelectronics and related fields for decades. These constants, namely the refractive index and extinction (or attenuation) coefficient, are the fundamental material properties that dictate electromagnetic field propagation in any medium. They form the inputs to well‐established models that allow for design and optimization of multilayer stack structures such as thin film solar cells, light‐emitting diodes, and photodetectors. These determinations are particularly challenging for materials that are scattering and highly absorbing. In this work, a new and resource‐efficient approach for optical constant determination based upon transmission spectrophotometry in combination with an iterative, reverse transfer matrix model and the Kramers–Kronig relation is reported. The approach is validated using more conventional ellipsometry for a number of functionally important semiconductors, including the recently emergent organic non‐fullerene electron acceptors (NFAs) and perovskites for which the optical constants in the UV–vis–near IR region are provided. Notably, the NFAs are found to present anomalously high refractive indices and extinction coefficients that are predicted to have a profound influence on the cavity electro‐optics of the new record efficiency organic solar cells of which they are key components.

Effect of Surface Treatment by Chemical-Mechanical Polishing for Transparent Electrode of Perovskite Solar Cells

Perovskite solar cells (PSCs) are usually fabricated by using the spin coating method. During the fabrication process, the surface status is very important for energy conversion between layers coated in the substrate. PSCs have multilayer-stacked structures, such as the transparent electrode layer, the perovskite layer, and a metal electrode. The efficiency and uniformity of all layers depend on the surface status of the transparent electrode coated on the glass substrate. Until now, etching methods by chemical processes have been introduced to make the substrate surface smooth and uniform by decreasing surface roughness. However, highly reactive chemical treatments can be harmful to the environment. In this study, we employed an eco-friendly chemical-mechanical polishing (CMP) process to ensure the fluorine-doped tin oxide (FTO) substrate is treated with a smooth surface. Before the perovskite layer and electron transport layer (ETL) are applied, the TiO2 layer is coated with the FTO substrate, and the surface of the FTO substrate is polished using CMP. As a result, the CMP-treated surface of the FTO substrate showed a smooth surface, and the PSCs with CMP treatment did not require conventional TiCl4 treatment.

Using a Multi-Layer Stacked AlGaN/GaN Structure to Improve the Current Spreading Performance of Ultraviolet Light-Emitting Diodes.

To obtain excellent current spreading performance of ultraviolet light-emitting diodes (UVLEDs), a 60-period stacked Si modulation-doped n-AlGaN/u-GaN structure is proposed to replace the traditional n-AlGaN structure. The high-resolution X-ray diffraction ω-scan rocking curves show that the periodic growth of AlGaN and GaN layers plays a positive role in reducing dislocation density. Compared with the conventional UV light-emitting diodes (LEDs), light emission micrographs of devices with a multi-layer stacked n-AlGaN/u-GaN structure reveal higher brightness and a more uniform distribution. In addition, the output power and external quantum efficiency under a 20-mA injection current are increased by 22% and 26.5%, respectively. Experimental and simulation results indicate that a multi-layer stacking structure can alleviate the current crowding effect in four ways: (1) a reduction in dislocation density; (2) replacement of quasi-two-dimensional electron transport with electronic bulk transport to enhance electron mobility; (3) an increase in electron concentration without improving the impurity concentration; and (4) a weakening of the electron scattering effect by reducing the impurity concentration.

Strain-mediated electric manipulation of magnetic skyrmion and other topological states in geometric confined nanodiscs

Magnetic skyrmions in multilayer stack structures are promising magnetic memory bits for applications in race-track storage devices or random-access memories. For practical implementation in energy efficient memory devices, it is essential to achieve a deterministic switch of skyrmion states, e.g. nucleation and elimination, triggered by electric fields. In this work, by means of micromagnetic simulation, we demonstrate the strain-mediated electric field driven switching of magnetic skyrmion and other topological states without the presence of a magnetic field in a proposed device consisting of nanodiscs of trilayer Pt/Co/Ta stacks on a piezoelectric substrate. It is revealed that the multiple magnetic state switching behaviors, including the nucleation and elimination of skyrmion or labyrinth stripe domain states, as well as topological transitions between skyrmion, vortex, skyrmionium and vertical single domain states, can be triggered by applying an external electric field mediated by strains. The corresponding critical strains and their dependence on the geometric parameters of the nanodiscs (e.g. size and number of stacks) for triggering such magnetic switching are also explored. The stability of these topological domain states and possible switching behaviors (e.g. volatile and non-volatile) between the different states are discussed as well. The capability for controlled switching of these topological states provides a new pathway to energy efficient high-density magnetoelectric memory and logic devices.

Stretchable and transparent supercapacitors based on extremely long MnO2/Au nanofiber networks

With the advances in the development of next-generation electronics, transparent and stretchable energy storage devices have received great attention due to their suitability for wearable electronics. However, it remains a great challenge to realize devices with high storage capacity and high degree of stretchability. This report describes a simple process for the fabrication of supercapacitors with areal capacitance of ~3.68 mF/cm2 and transmittance of ~60% of with high cycling stability tested over 8000 charging and discharging cycles. Extremely long MnO2/Au nanofiber networks electrode based on electrospinning is fabricated. This structure of the electrode enables the device to be highly stretchable. Additionally, the porous nature of MnO2 as well as the multilayer stacking structure of MnO2/Au nanofibers electrode enhances the areal capacitance of devices. As a prototype device, the supercapacitor in this study suggests a promising application for next-generation energy storage devices in transparent and wearable electronics.

GRASP depletion-mediated Golgi destruction decreases cell adhesion and migration via the reduction of α5β1 integrin.

The Golgi apparatus is a membrane-bound organelle that serves as the center for trafficking and processing of proteins and lipids. To perform these functions, the Golgi forms a multilayer stacked structure held by GRASP55 and GRASP65 trans-oligomers and perhaps their binding partners. Depletion of GRASP proteins disrupts Golgi stack formation and impairs critical functions of the Golgi, such as accurate protein glycosylation and sorting. However, how Golgi destruction affects other cellular activities is so far unknown. Here, we report that depletion of GRASP proteins reduces cell attachment and migration. Interestingly, GRASP depletion reduces the protein level of α5β1 integrin, the major cell adhesion molecule at the surface of HeLa and MDA-MB-231 cells, due to decreased integrin protein synthesis. GRASP depletion also increases cell growth and total protein synthesis. These new findings enrich our understanding on the role of the Golgi in cell physiology and provide a potential target for treating protein-trafficking disorders.

Implementation of Soft-Lithography Techniques for Fabrication of Bio-Inspired Multi-Layer Dielectric Elastomer Actuators with Interdigitated Mechanically Compliant Electrodes

Advancements in software engineering have enabled the robotics industry to transition from the use of giant industrial robots to more friendly humanoid robots. Soft robotics is one of the key elements needed to advance the transition process by providing a safer way for robots to interact with the environment. Electroactive polymers (EAPs) are one of the best candidate materials for the next generation of soft robotic actuators and artificial muscles. Lightweight dielectric elastomer actuators (DEAs) provide optimal properties such as high elasticity, rapid response rates, mechanical robustness and compliance. However, for DEAs to become widely used as artificial muscles or soft actuators, there are current limitations, such as high actuation voltage requirements, control of actuation direction, and scaling, that need to be addressed. The authors’ approach to overcome the drawbacks of conventional DEAs is inspired by the natural skeletal muscles. Instead of fabricating a large DEA device, smaller sub-units can be fabricated and bundled together to form larger actuators, similar to the way myofibrils form myocytes in skeletal muscles. The current study presents a novel fabrication approach, utilizing soft lithography and other microfabrication techniques, to allow fabrication of multilayer stacked DEA structures, composed of hundreds of micro-sized DEA units.

Joule heating-induced sp2-restoration in graphene fibers

Joule heating can instantaneously achieve high temperatures (>2000 °C) by applying electrical current on a resistive material. This ohmic heating by the passage of an electric current through a conducting domain may effectively heal the defective sites (i.e., vacancies, structural defects, and sp3 oxygen groups) of graphene oxide (GO) and revert them into sp2 domains. Indeed, the direction of electric field controls the texture of GO with preferential alignment, which significantly affects the transport properties along the fiber axis. Here we present electrical current-induced manipulation of resistive domain (i.e. Joule heating) as an effective healing method for the defect sites in GO fibers (GOFs). Systematic control of input current restores the sp2 lattice structures within fibers in a well-controlled manner. Structural evolution mechanism is proposed for multilayer stacked graphitic structures as well as graphene sheet plane under the reduction process. This defect-healing principle is rapid, environmentally benign and energy efficient, compared to other defect restoration methods, and yields tailored-aligned fibers with a high current-carrying capability and facile charge transport, which is potentially beneficial for power cables and other relevant applications.