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This study presents a comprehensive investigation of the impact of the deposition temperature on the HfxZr1−xO2 (HZO) ferroelectric layer of ferroelectric random access memory with TaN electrodes. This investigation mainly focuses on its electrical characteristics and compares the differences. It is revealed that the deposition temperature plays a crucial role in determining the crystal structure of HZO, which can exhibit a combination of tetragonal and orthorhombic phases or exist solely in one of the two phases. Furthermore, the grain size of HZO varies with the deposition temperature. These findings correspond well to the electrical measurement results, including leakage current, polarization, capacitance, and reliability tests. The study tracks the phase transition process during the operation of switching cycles when the phase transition process can be monitored as well. To better understand the observed differences, physical models that shed light on the underlying mechanisms affected by deposition temperature are proposed at the end of the article. [ABSTRACT FROM AUTHOR]

In this study, electrical measurements on ferroelectric random-access memory by prior x-ray irradiation are conducted. Compared with an unirradiated device, parameters such as current leakage and remnant polarization of the irradiated device were unexpectedly improved. Besides, better reliabilities including the number of endurance times and retention time have also been demonstrated. To clarify the underlying physical mechanism, the electrical properties are analyzed. The current–voltage curve (I–V) implies a change in the grain size in the ferroelectric layer (FL), and the capacitance–voltage curve (C – V) profile indicates that the FL undergoes a phase change during irradiation. Finally, according to the electrical results, a physical model is proposed as an explanation. [ABSTRACT FROM AUTHOR]

A method of using non‐volatile and fast ferroelectric field‐effect transistor (FeFET) devices to realize Boolean logic is proposed. First, the internal states are initialized. Then, the gate and body function as input terminals, which are used to write the states of the device, based on the voltage. Finally, the output signals can be easily read through the drain current. Of the 10 Institute of Electrical and Electronics Engineers (IEEE) standard logic gates, eight can be implemented using the proposed operation method alone and by following the definitions listed herein. Thus, to enable FeFET devices to act as functional logic gates, a simple operating method is proposed, providing substantial contributions to the development of computing in memory. The experimental results provide evidence of the efficacy of this method. [ABSTRACT FROM AUTHOR]

This work investigates the effect of X-ray accelerating voltage (Vacc) on the structural repair of HfZrOx ferroelectric random-access memory. We found that X-rays are able to break the molecular bonds due to missing electrons, thereby repairing the material structure. To further understand the influence of X-ray Vacc on structural repair, we conducted different Vacc conditions, with results showing that there is only a small improvement under high Vacc. However, the improvement is much clearer under low Vacc. To illuminate these results, we propose a physical model which is based on different X-ray energies that will have different energy penetration capacities. [ABSTRACT FROM AUTHOR]

In this study, an advanced supercritical fluid (SCF) technique that is suitable for materials and electronic devices with low temperature (80 °C) and high pressure (4000 psi) is proposed for a ZnO-based resistive random access memory (RRAM). After an SCF treatment, X-ray photoelectron spectroscopy (XPS) analysis confirms that the concentration of oxygen ions increases in the zinc oxide thin film. Moreover, electrical measurements confirm that the treated ZnO-based random access memory exhibits a lower forming voltage, lower set voltage, and higher ratio of high and low resistance states compared with a device without treatment. Next, the carrier transport mechanism is investigated by fitting the current–voltage curves. Finally, physical models are introduced to illustrate the extra oxygen ions that create better memory characteristics in the random access memory device after the SCF treatment. This significant SCF technique increases the content of oxygen ions without altering the original element ratio and maintains a simple device structure. Thus, the technique shows potential for feasible material improvement capable of effective real applications in the near future. [ABSTRACT FROM AUTHOR]

The HfZrOx (HZO) ferroelectric material is a promising material for ferroelectric memory and is compatible with the semiconductor process for ferroelectric random access memory (FeRAM) and negative capacitance field effect transistor. However, defects often exist in the grain boundary to influence the performance or reliability of devices. In addition, uniformity between devices must be considered when they are mass-produced. Therefore, the grain size will become important in determining the performance and reliability. In this study, we use electrical measurements of current–voltage, capacitance–voltage, and polarization–voltage measurements to test high- and low-temperature deposition devices, with a transmission electron microscope (TEM) image to confirm the grain size. Finally, we propose a model to explain the phenomenon and provide a method to obtain better ferroelectric memory. [ABSTRACT FROM AUTHOR]

This paper studies a composite device composed of ferroelectric random access memory (FeRAM) and metal-oxide-semiconductor field effect transistor. The relationship between the hysteresis characteristics and VG is reported, and the on/off ratios under different writing voltages are presented. The gm–VG curve of the forward and reverse sweeping shows that under forward sweep a very clear instability appears while voltage increases. The reasons for this can be explained according to the voltage divider rule, the ID formula, and gm formula of transistors, which show that there is polarization of the ferroelectric material. Accordingly, a method is proposed to determine the critical point of the ferroelectric capacitor polarization in this 1T1C structure, which is advantageous because it identifies the appropriate reading voltage necessary for an effective program state of the 1T1C device. This method was shown in three 1T1C and three FeRAMs devices with different ferroelectric areas. Finally, this method was verified by the P–V loop of FeRAMs. [ABSTRACT FROM AUTHOR]

In this work, Ag-doped HfO2-based resistive random access memory (RRAM) with high on-off ratio, low-power consumption and forming-free properties was investigated. We propose the fabrication flow of the RRAM with via-hole structure. After doping Ag into HfO2 as the switching layer, the devices could execute resistive switching without a high-voltage forming process. The conduction mechanism was subsequently validated by a current fitting analysis. Electric field simulation was also utilized to observe the electric field distribution and finally a physical model was proposed to provide an explanation for the formation and dissolution of the filament. [ABSTRACT FROM AUTHOR]

In this study, a one transistor one resistor (1T1R) structure combining a fin‐like low‐temperature polycrystalline‐silicon (LTPS) transistor and a resistive random access memory (RRAM) is successfully fabricated. For the fin‐like LTPS transistor, both n‐type and p‐types show excellent electrical output characteristics. Fin‐like structure produces more stable output characteristics. Also, the forming and current–voltage (I–V) characteristics are measured in this study, and the RRAM exhibits a forming voltage of about −1.9 V. As for the I–V switching property, the devices are stable and show excellent performance, with the set and reset voltages showing only minimal change over 100 cycles. Moreover, combining the fin‐like LTPS transistor and RRAM into a 1T1R structure results in favorable operation over 100 cycles, with excellent retention and endurance. According to these results, RRAM can be successfully combined with a fin‐like LTPS transistor for application in current integrated circuit processes without difficulty. [ABSTRACT FROM AUTHOR]

In this letter, the electrical characteristics of Ti/HfO2/TiN resistive random access memory (RRAM) were thoroughly investigated. An abnormal current degradation was seen in the DC sweeping cycle. Both the on-state and off-state current clearly exhibited degradation with time. Next, current fitting analysis was used to investigate the carrier transport mechanisms. The results indicate that the on-state carrier transport mechanism changed from space-charge-limited current into hopping conduction after cycle sweeping. However, the off-state current changes from Schottky thermal emission to hopping conduction. Based on comparisons of different Schottky distances and Schottky barriers, physical models were proposed to explain the abnormal current degradation behavior. Finally, COMSOL electric field simulations were used to show the electric field distribution around the conducting filament (CF), and the conducting model was subsequently verified. [ABSTRACT FROM AUTHOR]

Thymoma is a rare tumour that often occurs in the anterior mediastinum. Thymomas are usually diagnosed in middle-aged patients, and nearly half of cases are associated with myasthenia gravis. Thymomas typically progress through direct invasion of the thoracic cavity with extra-thoracic distant metastasis being uncommon. Here we report the case of a male patient who underwent an extensive thymectomy and radiotherapy 10 years before presentation, and in whom we detected a spleen tumour during regular out-patient follow-up. The patient underwent a splenectomy, and a final diagnosis of type B3 malignant thymoma was established. [ABSTRACT FROM AUTHOR]

Background: The mechanism of oral squamous cell carcinoma (SCC) invading jawbone remains controversial. Interactions between receptor activator of NF-κB (RANK) and its ligand (RANKL) are required for osteoclastogenesis. The binding of RANK and RANKL induces differentiation of osteoclasts, leading to bony destruction. Osteoprotegerin (OPG), a decoy receptor for RANKL, also binds to RANKL by competing with RANK, and this could protect against osseous destruction. Materials and methods: Immunoexpression of RANKL, RANK, and OPG in 25 cases of human buccal SCCs without bony invasion and 15 cases of gingival SCCs with mandibular bony invasion was investigated. Normal oral mucosa from five individuals without betel-quid chewing or cigarette smoking was used as a control. The scores are designated as percentage of positive staining × intensity of staining for each section. Results: Strong cytoplasmic staining of RANKL proteins is detected in cancer cells of both buccal and gingival SCCs. The same protein is identified in cytoplasm of osteoclasts for all cases involving bony invasion. Strong cytoplasmic staining of RANKL is confined to basal layer for all normal mucosa. A similar staining pattern is noted for RANK protein in all buccal and gingival SCCs. An absence of staining of RANK protein is noted for all normal tissues. Weak to negative cytoplasmic stained OPG protein is present in all buccal and gingival SCCs, but is absent in all normal tissues. Conclusion: These findings suggest the potential value of the RANK/RANKL/OPG pathway as biomarkers in human oral SCCs. [ABSTRACT FROM AUTHOR]

Betel quid (BQ) products, with or without tobacco, have been classified by the International Agency for Research on Cancer (IARC) as group I human carcinogens that are associated with an elevated risk of oral potentially malignant disorders (OPMDs) and cancers of the oral cavity and pharynx. There are estimated 600 million BQ users worldwide. In Taiwan alone there are 2 million habitual users (approximately 10% of the population). Oral and pharyngeal cancers result from interactions between genes and environmental factors (BQ exposure). Cytochrome p450 (CYP) families are implicated in the metabolic activation of BQ- and areca nut-specific nitrosamines. In this review, we summarize the current knowledge base regarding CYP genetic variants and related oral disorders. In clinical applications, we focus on cancers of the oral cavity and pharynx and OPMDs associated with CYP gene polymorphisms, including CYP1A1, CYP2A6, CYP2E1, and CYP26B1. Our discussion of CYP polymorphisms provides insight into the importance of screening tests in OPMDs patients for the prevention of oral and pharyngeal cancers. Future studies will establish a strong foundation for the development of chemoprevention strategies, polymorphism-based clinical diagnostic tools (e.g., specific single-nucleotide polymorphism (SNP) "barcodes"), and effective treatments for BQ-related oral disorders. [ABSTRACT FROM AUTHOR]