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1.
    
With the rapid development of the information age, more and more new technologies such as big data and cloud computing are beginning to emerge. As a result, the demand for high data‐storage density is becoming more and more urgent. In the past 10 years, data‐storage density has been greatly improved by reducing the size of memory cells. However, as semiconductor technology nodes have shrunk, a number of problems have appeared in metal–oxide–semiconductor field‐effect transistor (MOSFET)‐based memory cells, such as gate‐induced drain leakage, drain‐induced barrier lowering, and reliability issues. Fortunately, due to their atomic thickness, high mobility, and sustainable miniaturization properties, 2D atomic crystals (2D materials) are considered the most promising substitute for silicon to solve those issues. This review investigates the use of 2D materials in nonvolatile and volatile memories, including MOSFET‐based memory, magnetic random‐access memory, resistive random‐access memory, dynamic random‐access memory, semi‐floating‐gate memory, and other novel memories.  相似文献   

2.
    
Van der Waals (vdW) heterostructures with 2D materials have shown that atomically thin non-volatile memories are advantageous in terms of integration, while offering high performance and excellent stability. The non-volatile memory behavior of 2D materials has mainly been studied for single-bit operation, and there is growing interest in expanding to multi-bit operation to enhance the storage capacities of memory devices. However, the conditions or rules for generating the desired number of bits in 2D-based multi-bit memory remain to be identified. In this study, multiple bits are successfully created on non-volatile memory based on vdW heterostructure floating-gate memory (FGM) by systematically tuning the dimensions of the 2D materials. In particular, a fingerprint mechanism is established that links the bit number and dimensions of 2D crystals on vdW heterostructures. This approach could enable the precise generation of the desired number of bits in layered-material-based vdW FGMs.  相似文献   

3.
    
Miniaturization of device elements, such as ferroelectric diodes, depends on the downscaling of ferroelectric film, which is also crucial for developing high‐density information storage technologies of ferroelectric random access memories (FeRAMs). Recently emerged ferroelectric two‐dimensional (2D) van der Waals (vdWs) layered materials bring an additional opportunity to further increase the density of FeRAMs. A lateral, switchable rectifier is designed and fabricated based on atomically thin 2D α‐In2Se3 ferroelectric diodes, thus breaking the thickness limitation of conventional ferroelectric films and achieving an unprecedented level of miniaturization. This is realized through the interrelated coupling between out‐of‐plane and in‐plane dipoles at room temperature; that is, horizontal polarization reversal can be effectively controlled through a vertical electric field. Being further explored as a switchable rectifier, the obtained maximum value of rectification ratio for the α‐In2Se3 based ferroelectric diode can reach up to 2.5 × 103. These results indicate that 2D ferroelectric semiconductors can offer a pathway to develop next‐generation multifunctional electronics.  相似文献   

4.
    
Two‐dimensional (2D) materials have the potential to extend state‐of‐the‐art semiconductor technology to sub‐nanometer scales and have inspired numerous research efforts exploring novel device structures. The key elements of electron devices, including low‐resistance contacts and reliable gate dielectrics, have to be optimized to complete a functional device. This review highlights recent studies on the integration of ferroelectrics with 2D materials to implement 2D electron devices. The high polarization field and ultra‐high dielectric constants of ferroelectric materials enable versatile carrier tuning in 2D materials. Various novel device structures and functionalities are enabled with the integration of ferroelectrics and 2D materials. Representative examples, including ferroelectric‐gated 2D memory devices, low‐power field‐effect transistors enabled by high‐k ferroelectrics and negative capacitance effect, and optothermal and photoelectronic devices, are reviewed. Current developments and remaining challenges in ferroelectric‐gated 2D electron devices are discussed.  相似文献   

5.
    
2D transition metal dichalcogenides (TMDs) are promising semiconductive films for applications in future devices due to their prosperous and tunable band structures. However, most TMD-based top gate transistors suffer from a significant doping effect in the channel due to the subsequent deposition high-k dielectric layer and metal gate, which limits their practical applications. In this work, the channel doping effect caused by various processing steps based on mechanical exfoliated MoS2 sheets is systematically investigated. This work illustrates a clear correlation among these steps and provides a simple and efficient methodology to realize high-performance enhancement mode MoS2 field effect transistors, which can be extended to other 2D materials.  相似文献   

6.
    
Low‐power, nonvolatile memory is an essential electronic component to store and process the unprecedented data flood arising from the oncoming Internet of Things era. Molybdenum disulfide (MoS2) is a 2D material that is increasingly regarded as a promising semiconductor material in electronic device applications because of its unique physical characteristics. However, dielectric formation of an ultrathin low‐k tunneling on the dangling bond‐free surface of MoS2 is a challenging task. Here, MoS2‐based low‐power nonvolatile charge storage memory devices are reported with a poly(1,3,5‐trimethyl‐1,3,5‐trivinyl cyclotrisiloxane) (pV3D3) tunneling dielectric layer formed via a solvent‐free initiated chemical vapor deposition (iCVD) process. The surface‐growing polymerization and low‐temperature nature of the iCVD process enable the conformal growing of low‐k (≈2.2) pV3D3 insulating films on MoS2. The fabricated memory devices exhibit a tunable memory window with high on/off ratio (≈106), excellent retention times of 105 s with an extrapolated time of possibly years, and an excellent cycling endurance of more than 103 cycles, which are much higher than those reported previously for MoS2‐based memory devices. By leveraging the inherent flexibility of both MoS2 and polymer dielectric films, this research presents an important milestone in the development of low‐power flexible nonvolatile memory devices.  相似文献   

7.
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8.
Room temperature ferroelectric thin films are the key element of high-density nonvolatile memories in modern electronics. However, with the further miniaturization of the electronic devices beyond the Moore’s law, conventional ferroelectrics suffer great challenge arising from the critical thickness effect, where the ferroelectricity is unstable if the film thickness is reduced to nanometer or single atomic layer limit. Two-dimensional(2D) materials, thanks to their stable layered structure, saturate interfacial chemistry, weak interlayer couplings, and the benefit of preparing stable ultra-thin film at 2D limit, are promising for exploring 2D ferroelectricity and related device applications. Therefore, it provides an effective approach to overcome the limitation in conventional ferroelectrics with the study of 2D ferroelectricity in van der Waals(vdW) materials. In this review article,we briefly introduce recent progresses on 2D ferroelectricity in layered vdW materials. We will highlight the study on atomically thin α-In2Se3, which is an emergent ferroelectric semiconductor with the coupled in-plane and out-of-plane ferroelectricity. Furthermore, two prototype ferroelectric devices based on ferroelectric α-In2Se3 will also be reviewed.  相似文献   

9.
    
The investigation of two‐dimensional (2D) ferroelectrics has attracted significant interest in recent years for applications in functional electronics. Without the limitation of a finite size effect, 2D materials with stable layered structures and reduced surface energy may go beyond the presence of an enhanced depolarization field in ultrathin ferroelectrics, thereby opening a pathway to explore low‐dimensional ferroelectricity, making ultra‐high‐density devices possible and maintaining Moore's Law. Although many theoretical works on potential 2D ferroelectric materials have been conducted, much still needs to be accomplished experimentally, as it is rare for 2D ferroelectric materials to be proven and plenty of 2D ferroelectrics are waiting to be discovered. First, experimental and theoretical progress on 2D ferroelectric materials, including in‐plane and out‐of‐plane, is reviewed, followed by a general introduction to various characterization methods. Intrinsic mechanisms associated with promising 2D ferroelectric materials, together with related applications, are also discussed. Finally, an outlook for future trends and development in 2D ferroelectricity are explored. Researchers can use this to obtain a basic understanding of 2D ferroelectric materials and to build a database of progress of 2D ferroelectrics.  相似文献   

10.
    
With the advent of the post Moore era, modern electronics require further device miniaturization of all electronic components, particularly ferroelectric memories, due to the need for massive data storage. This demand stimulates the exploration of robust switchable ferroelectric polarizations at the atomic scale. In this scenario, van der Waals ferroelectrics have recently gained increasing attention because of their stable layered structure at nanometer thickness, offering the opportunity to realize two-dimensional ferroelectricity that is long-sought in conventional thin film ferroelectrics. In this review, recent advancements are summarized in layered ferroelectrics with highlights of the fundamentals of intrinsic two-dimensional ferroelectricity, the emergence of artificial stacking ferroelectricity, and related protype devices with exotic functions. In addition, the unique polarization control in van der Waals ferroelectrics is discussed. Although great challenges remain unsolved, these studies undoubtedly advance the integration of 2D ferroelectrics in electronics.  相似文献   

11.
    
Ferroelectricity in ultrasonically exfoliated flakes of the layered Aurivillius oxide Bi5Ti3Fe0.5Co0.5O15 with a range of thicknesses is studied. These flakes have relatively large areas (linear dimensions many times the film thickness), thus classifying them as 2D materials. It is shown that ferroelectricity can exist in flakes with thicknesses of only 2.4 nm, which equals one‐half of the normal crystal unit cell. Piezoresponse force microscopy (PFM) demonstrates that these very thin flakes exhibit both piezoelectric effects and that the ferroelectric polarization can be reversibly switched. A new model is presented that permits the accurate modeling of the field‐on and field‐off PFM time domain and hysteresis loop responses from a ferroelectric during switching in the presence of charge injection, storage, and decay through a Schottky barrier at the electrode–oxide interface. The extracted values of spontaneous polarization, 0.04(±0.02) C m−2 and electrostrictive coefficient, 2(±0.1) × 10−2 m4 C−2 are in good agreement with other ferroelectric Aurivillius oxides. Coercive field scales with thickness, closely following the semi‐empirical scaling law expected for ferroelectric materials. This constitutes the first evidence for ferroelectricity in a 2D oxide material, and it offers the prospect of new devices that might use the useful properties associated with the switchable ferroelectric spontaneous polarization in a 2D materials format.  相似文献   

12.
    
X‐ray detectors with high sensitivity are of great significance in both civil and military fields. Over the past decades, great efforts have been made to improve the sensitivity in conventional inorganic materials, but mainly at the cost of increasing the energy consumption with a quite high operating voltage. Developing photosensitive ferroelectrics directly as detector materials may be a conceptually new strategy in view of the strong ferroelectric spontaneous polarization (Ps) that assists photoinduced carriers separation and transport. A high‐performance X‐ray detector in 2D hybrid halide perovskite ferroelectric (C4H9NH3)2(C2H5NH3)2Pb3Br10 ( BA2EA2Pb3Br10 ) (Ps = 5 µC cm?2) is fabricated and exhibits an ultrahigh X‐ray sensitivity up to 6.8 × 103 µC Gyair?1 cm?2 even at a relatively low operating voltage, which is over 300‐fold larger than that of state‐of‐the‐art α‐Se X‐ray detectors. Such a brilliant figure‐of‐merit is largely attributed to the superior mobility–lifetime products associated with the strong ferroelectric polarization of BA2EA2Pb3Br10 . As pioneering work, these findings inform the exploration of hybrid halide perovskite ferroelectrics toward high‐performance photoelectronic devices.  相似文献   

13.
介绍了在纳米晶浮栅存储器数据保持特性方面的研究工作,重点介绍了纳米晶材料的选择与制备和遂穿介质层工程。研究证明,金属纳米晶浮栅存储器比半导体纳米晶浮栅存储器具有更好的电荷保持特性。并且金属纳米晶制备方法简单,通过电子束蒸发热退火的方法就能够得到质量较好的金属纳米晶,密度约4×1011cm-2,纳米晶尺寸约6～7nm。实验证明,高介电常数隧穿介质能够明显改善浮栅存储器的电荷保持特性,所以在引入金属纳米晶和高介电常数遂穿介质之后,纳米晶浮栅存储器可能成为下一代非挥发性存储器的候选者。  相似文献   

14.
蔡苇  符春林  陈刚 《半导体技术》2007,32(2):97-100
综述了超薄SiO2栅介质层引起的问题、MOS栅介质层材料的要求、有希望取代传统SiO2的高k栅介质材料的研究进展.提出了高k栅介质材料研究中需进一步解决的问题.  相似文献   

15.
用二维模拟软件 ISE研究了典型的 70 nm高 K介质 MOSFETs的短沟性能 .结果表明 ,由于 FIBL 效应 ,随着栅介质介电常数的增大 ,阈值电区减小 ,而漏电流和亚阈值摆幅增大 ,导致器件短沟性能退化 .这种退化可以通过改变侧墙材料来抑制  相似文献   

16.
    
The rapid development in information technologies necessitates rapid advancements of their supporting hardware. In particular, new computing paradigms are needed to overcome the bottleneck of traditional von Neumann architecture. Bottom-up innovation, especially at the materials and devices level, has the potential to disrupt existing technologies through their emergent phenomena. As a new type of conceptual device, 2D ferroelectric field-effect transistor (FeFET) is highly sought after due to its potential integration with modern semiconductor processes. Its low power consumption, area efficiency, and ultra-fast operation provide an extra edge over traditional technologies. This review highlights recent developments in 2D FeFET, covering their device construction, working mechanisms, 2D ferroelectric polarization mechanism, multi-functional applications and prospects. In particular, the combination of 2D semiconductor and ferroelectric dielectric materials for multi-functionality applications is discussed. This includes non-volatile memories (NVM), neural network computing, non-volatile logic operation, and photodetectors. As a novel device platform, 2D semiconductor and ferroelectric interfaces are bestowed with a plethora of emergent physical mechanisms and applications.  相似文献   

17.
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18.
    
A molecular nano‐floating gate (NFG) of pentacene‐based transistor memory devices is developed using conjugated polymer nanoparticles (CPN) as the discrete trapping sites embedded in an insulating polymer, poly (methacrylic acid) (PMAA). The nanoparticles of polyfluorene (PF) and poly(fluorene‐alt‐benzo[2,1,3]thiadiazole (PFBT) with average diameters of around 50–70 nm are used as charge‐trapping sites, while hydrophilic PMAA serves as a matrix and a tunneling layer. By inserting PF nanoparticles as the floating gate, the transistor memory device reveals a controllable threshold voltage shift, indicating effectively electron‐trapping by the PF CPN. The electron‐storage capability can be further improved using the PFBT‐based NFG since their lower unoccupied molecular orbital level is beneficial for stabilization of the trapped charges, leading a large memory window (35 V), retention time longer than 104 s with a high ON/OFF ratio of >104. In addition, the memory device performance using conjugated polymer nanoparticle NFG is much higher than that of the corresponding polymer blend thin films of PF/polystyrene. It suggests that the discrete polymer nanoparticles can be effectively covered by the tunneling layer, PMAA, to achieve the superior memory characteristics.  相似文献   

19.
    
Developing 2D reconfigurable multifunctional devices is of great potential in further miniaturizing the chip area and simplifying circuit design. 2D van der Waals (vdW) heterostructures offer a novel approach to realizing reconfigurable multifunctional devices. Despite the numerous previous reports that have integrated various functions in a single 2D heterostructures device, most of those devices are based on a complex multilayer heterostructure or an air-unstable channel material, limiting their ability to be applied in integrated circuits. There is an urgent need to develop 2D reconfigurable multifunctional devices that have a simple structure and stable electrical properties. In this work, a side-gate reconfigurable device is illustrated based on simple BN-MoS2 vdW heterostructures. Three different functions in a single device have been achieved, including a diode, double-side-gate reconfigurable logic transistor, and top floating gate memory. A lateral n+-n homojunction is created along the MoS2 channel and the rectification ratio is above 105. Reconfigurable logic operations (OR, AND) can be achieved in a single double-side-gate device and the current on/off ratio is ≈t 104. Moreover, the device can act as a floating gate memory under back gate operation. Those results pave the way for integrating the same reconfigurable multifunctional devices to realize complex electronic systems.  相似文献   

20.
林钢  徐秋霞 《半导体学报》2004,25(12):1717-1721
以等效氧化层厚度(EOT)同为2.1nm的纯SiO2栅介质和Si3N4/SiO2叠层栅介质为例,给出了恒定电压应力下超薄栅介质寿命预测的一般方法,并在此基础上比较了纯SiO2栅介质和Si3N4/SiO2叠层栅介质在恒压应力下的寿命.结果表明,Si3N4/SiO2叠层栅介质比同样EOT的纯SiO2栅介质有更长的寿命,这说明Si3N4/SiO2叠层栅介质有更高的可靠性.  相似文献   

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