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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]

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 study investigates the properties of a onetransistor- one-capacitor (1T1C) device that includes a transistor and ferroelectric random access memory (FeRAM) at the nanoscale. The hysteresis characteristics are presented. A simultaneous measurement of writing and reading was used. A difference was observed between the forward and reverse transconductance (gm) −VG curves, and the reason can be explained by the relationship between the operating voltage and coercive voltages. According to the relationship between gm and polarization, the polarization signal can be obtained using gm at the nano-scale. The remnant polarization of the 1T1C device per unit ferroelectric-layer area was confirmed by the polarization value of FeRAM via the Positive Up Negative Down method. Finally, the P–V loops obtained using gm values with different measurement ranges are also reported. [ABSTRACT FROM AUTHOR]

The effect of different pulse rise time in resistive random access memory (RRAM) is presented in this study. The result shows that the length of pulse rise time will lead to variations in RRAM OFF-state resistance that occur due to which of two distinct effects governs the reaction, either the electric field or the thermal field. Different sidewall materials are adopted in RRAM devices to verify these phenomena, and a physical model supplemented with COMSOL simulation is proposed. [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]

This study investigates an improvement in memory characteristics through depositing an In2O3 layer as an oxygen ion reservoir in the switching layer (SL) of resistive random access memory (RRAM). The deposition of In2O3, denoted as Pt/HfO2/In2O3/TiN device, provides better memory characteristics including lower forming voltage (VF), set/reset voltage (VSET/VRESET), larger memory window, and higher resistances with higher uniformity at low resistance state (LRS) and high resistance state (HRS), compared to the devices without the In2O3 deposition, denoted as Pt/HfO2/TiN device. The conduction mechanisms, verified through fitting current–voltage (I - V) curves, are consistent with the results of a varied temperature I - V experiment. Finally, a physical model is proposed to explain our observations. [ABSTRACT FROM AUTHOR]

HfZrOx (HZO)-based materials have received much attention due to their special film characteristics in recent years. Ferroelectric random access memory (FeRAM) based on this HZO material also has promising potential as a next generation memory due to its non-volatile characteristics, excellent endurance, and low power consumption. Previous research has mainly focused on the material properties of HZO-based FeRAM. However, an in-depth investigation of the electrical properties of HZO-based FeRAM is necessary to better understand its transporting mechanism. In this contribution, this study aims to investigate the mechanism of an HZO-based metal–ferroelectric-metal capacitor using comprehensive experimental results, including current–voltage, capacitance–voltage, and polarization–voltage measurements. Experiments at various temperatures are also conducted to help verify the transport mechanism. The low current transport by the Fowler–Nordheim tunneling mechanism does not change with temperature, whereas the high current transport via the Schottky mechanism increases with increasing temperature. We found that the orientation of the dipole plays an important role. Finally, we also propose a band model to explain the electron transport in this HZO-based FeRAM. [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 experiment, the electrical performance of zinc oxide based-resistive random access memory (RRAM) is successfully improved by using annealing in ammonia hydroxide solution at low-temperature and high pressure to complete ammonium-doped ZnO based-RRAM. The results of material analysis indicate that using CO2 as ammonia hydroxide carrier during the annealing process leads to the reduction in dangling bond density. This can be clearly observed in the decrease in breakdown voltage during the forming process and a lower operating current during operation. Furthermore, in this ammonium-doped ZnO based-RRAM, we study the molecular doping of NH3 in ZnO, where the endurance and retention properties are improved as well. These improvements can be attributed to the higher concentration of nitrogen in the switching layer, which can effectively control the active oxygen ions during the operation process. [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]

This article explains the difference in the reset processes between single RRAM and 1T1R RRAM structures. In the single RRAM, as the reset voltage increases, the off-state resistance increases. This is a normal RRAM operation. However, in the 1T1R structure, the reset voltage increases while the OFF-state resistance does not increase. This may be caused by either current or voltage being insufficient to switch the RRAM to its higher resistance state. The measurements of real voltage indicate that the insufficient voltage is in fact the main cause. For the 1T1R RRAM structure, if it is to be reset to a higher resistance state, it is best done by increasing the gate voltage to increase the OFF-state resistance. Therefore, we provide a method to reduce the misjudgment in the array, and it would be beneficial for the development of high-density memory. [ABSTRACT FROM AUTHOR]

In this paper, we investigate two different resistive switching mechanisms in sputtered nickel oxide thin film which result from using the forming compliances of 15 μA and 15 mA. X-ray photoelectron spectroscopy material analysis results verify the nickel and oxygen chemical shifts, while energy-dispersive X-ray spectroscopy results confirm oxygen content changes after the forming process. Moreover, two markedly different resistive switching mechanisms, those of unipolar and bipolar, are accomplished in a single nickel oxide thin film. To clarify the two resistance switching mechanisms in the Pt/NiO/TiN device, a size effect measurement was conducted to determine the filament-type conduction. Moreover, the device capability to act as a memory device utilizing these two switching behaviors was determined, and a retention test for reliability was also carried out over 125 °C. Finally, the switching mechanism was confirmed by current fitting and sampling reset methods, and an appropriate physical model is presented. We anticipate this model can provide an insight into further future applications of RRAM devices. • We have examined the unipolar and bipolar resistive switching (RS) characteristics using different forming compliance. • The physical mechanisms were confirmed by current fitting and constant voltage sampling results. • The physical models were established to explain two switching characteristics. [ABSTRACT FROM AUTHOR]

A technique was proposed to concentrate the distribution of set voltages. After a plasma treatment, the stability of the high-resistive state (HRS) increased, and the distribution of set voltages was more concentrated at 0.8 V, with a sufficient HRS/LRS resistive ratio (∼100x). In addition, the surface of the TiN electrode became rougher, causing oxygen to enter the TiN electrode and form a TiON layer, which acts as an oxygen reservoir. The reservoir is confirmed and the conduction model is supported by both electrical and material analyses. We propose that the observed improvement is due to the difference in the TiN electrode surface. Image 1 • Applied the plasma treatment on electrode to stabilize set voltage. • Construct the physical model to explain abnormal current conduction. • Complete electrical and material analysis were performed in this work. [ABSTRACT FROM AUTHOR]