- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Handbook of Mechanics of Materials || Surface/Interface Stress and Thin Film Stress
摘要： Thin ?lm stress is critical for the reliability and electronic/optoelectronic properties of thin ?lm devices. In this chapter, we systematically discussed the effects of surface and interface stresses on the ?lm stress development during growth of polycrystalline ?lms at the initial and ?nal growth stage. We demonstrate that surface stress plays an important role at the initial stage of ?lm growth (island growth stage), and conventional stress analysis technology such as wafer curveture experiments may not be applicable at this stage. At the late stage of ?lm growth, we also show that adatom insertion into the grain boundaries is the primary mechanism of compressive stress development.
关键词： interface stress,Thin ?lm stress,adatom insertion,wafer curvature,grain boundaries,surface stress,polycrystalline ?lms
更新于2025-09-10 09:29:36
-
Highly enhanced solar conversion efficiency of novel layer-by-layer PbS:Hg and CdS quantum dots-sensitized ZnO thin films prepared by sol–gel spin coating
摘要： Owing to superior optical properties, ZnO thin ?lms have immense potential in solar cell preparation. ZnO thin ?lms were prepared by sol–gel technology. However, this is prolonged technique and it necessitates a complex precursor solution. In the present work, ZnO thin ?lms are prepared by sol–gel spin coating with simple precursor, zinc acetate. A very remarkable feature of the method is that polycrystalline, non-abrasive and translucent ?lms were obtained. Additionally, novel PbS:Hg quantum dots (QDs) and CdS QDs are successfully synthesized. Moreover, both types of QDs are deposited layer-by-layer over pure ZnO and Ag:ZnO thin ?lms. The ?lms are characterized by X-ray diffraction, and crystallinity continuation is observed even after the addition of QDs layer. Presence of synthesized QDs over thin ?lms is also con?rmed. The ?lms were also characterized by scanning electron microscopy (SEM) and UV–Vis spectroscopy. Uniform, dense and porous surface morphology is clearly revealed. Sensitized thin ?lms show a huge decline in band gap and large enhancement in ef?ciency. Superior current density (10.87 mA cm?2) is achieved with PbS:Hg/CdS/Ag:ZnO, which leads to enhancement in overall solar conversion ef?ciency by 6.34 times.
关键词： PbS:Hg quantum dots,sol–gel,Ag:ZnO ?lm,CdS quantum dots
更新于2025-09-10 09:29:36
-
Frequency response study of surface acoustic wave devices with SiO <i> <sub/>x</sub></i> N <i> <sub/>y</sub></i> film using LiTaO <sub/>3</sub> substrate
摘要： In an attempt to suppress the frequency variation of a surface acoustic wave device caused by dielectric ?lm deposition on an interdigital transducer (IDT) electrode, we fabricated a one-port resonator and examined the correlation with frequency response and refractive index when a SiOxNy ?lm is deposited. Our data showed that the resonator frequency changes as the refractive index of the SiOxNy ?lm changes. We also found that the frequency drift caused by the SiOxNy deposition can be suppressed if the refractive index is kept in a certain range. Then, we performed a ?nite element method spectral domain analysis to calculate frequency response using the Young’s modulus obtained in this experiment. The calculated frequency response indicated that the refractive index of the SiOxNy ?lm needs to be altered in accordance with the IDT electrode thickness. We suggest that one of the e?ective ways of controlling the frequency response is to manage the refractive index of SiOxNy.
关键词： SiOxNy ?lm,frequency response,refractive index,IDT electrode,surface acoustic wave device
更新于2025-09-10 09:29:36
-
Effects of source/drain-electrode material, thickness and fabrication method on the electrical performance of pentacene thin-film transistor
摘要： The e?ects of source/drain (S/D) electrode material (Ni, Pt and Pd) and deposition method (electron-beam evaporation and sputtering) on the performance of pentacene organic thin-?lm transistor (OTFT) are studied. Experimental results show that the OTFT with Pd S/D electrodes deposited by sputtering exhibits the best electrical performance. This should be due to the small charge-injection barrier at the pentacene/electrode interface and small thermal load generated during the metal deposition. Besides, through varying the Pd S/D electrode thickness, it is found that increasing the electrode thickness results in performance degradation due to degraded pentacene/electrode interface, which is caused by higher thermal stress developed during longer deposition time.
关键词： Organic thin-?lm transistor,Contact metal,Electrode thickness,Fabrication method
更新于2025-09-10 09:29:36
-
A Review for Compact Model of Thin-Film Transistors (TFTs)
摘要： Thin-?lm transistors (TFTs) have grown into a huge industry due to their broad applications in display, radio-frequency identi?cation tags (RFID), logical calculation, etc. In order to bridge the gap between the fabrication process and the circuit design, compact model plays an indispensable role in the development and application of TFTs. The purpose of this review is to provide a theoretical description of compact models of TFTs with different active layers, such as polysilicon, amorphous silicon, organic and In-Ga-Zn-O (IGZO) semiconductors. Special attention is paid to the surface-potential-based compact models of silicon-based TFTs. With the understanding of both the charge transport characteristics and the requirement of TFTs in organic and IGZO TFTs, we have proposed the surface-potential-based compact models and the parameter extraction techniques. The proposed models can provide accurate circuit-level performance prediction and RFID circuit design, and pass the Gummel symmetry test (GST). Finally; the outlook on the compact models of TFTs is brie?y discussed.
关键词： thin-?lm transistors (TFTs),surface potential,compact model
更新于2025-09-09 09:28:46
-
High-mobility material research for thin-film transistor with amorphous thallium–zinc–tin oxide semiconductor
摘要： The applicability of thallium–zinc–tin oxide (TlZnSnO) as a channel material for a thin-?lm transistor (TFT) was investigated by ?rst-principles simulation and cosputtering experiment with XZnSnO (X = Al, Ga or In). The electron effective mass (m*) of Tl0.4ZnSnO was simulated to be >0.153, which is much smaller than that of In0.4ZnSnO (0.246). An In0.4ZnSnO TFT exhibited a mobility (μ) of 32.0 cm2 V%1 s%1 in the experiment; therefore, the Tl0.4ZnSnO TFT was expected to have a higher mobility of approximately 50 cm2 V%1 s%1 following the relation (μ / 1/m*). Moreover, the Tl-related oxide semiconductor would provide better TFT stability because its oxide vacancy is more stable than that of an In-related oxide semiconductor.
关键词： first-principles simulation,thallium–zinc–tin oxide,mobility,cosputtering,electron effective mass,thin-?lm transistor
更新于2025-09-09 09:28:46
-
Nanometer-Sized Crystalline Clusters of IGZO Films Determined from the Grazing Incidence X-ray Scattering and Anomalous X-ray Scattering Data Combined with Reverse Monte Carlo Simulations
摘要： Grazing incidence X-ray scattering measurements have been carried out on c-axis aligned crystalline-indium gallium zinc oxide (CAAC-IGZO) ?lm and nanocrystalline category-indium gallium zinc oxide (NC-IGZO) ?lm and the following results were obtained: (1) the characteristic layered structure of the IGZO crystal did not hold its shape and the X-ray scattering pro?le showed only a relatively sharp ?rst peak at the wave vector (Q) = 21.8 for CAAC ?lm and 23.1 nm11 for NC ?lm, respectively, and additional weak broad peaks were observed at a higher angle. (2) In the case of the CAAC ?lm, tiny peaks were observed at Q = 7 and 14 nm11, corresponding to the positions of the 003 and 006 re?ections, respectively, of the IGZO crystal. Such tiny peaks were not detected in the case of NC ?lm but the asymmetry of the ?rst peak at the low angle side was clearly observed. (3) These structural features implied that more than three polyhedral units, such as InOx (x = 4-6), GaOy (y = 4-6), and ZnOz (z = 4-6), were likely to coexist. It is appropriate to call this structural feature as cluster-1. (4) A composite-type structure formed by combining these polyhedral units is also likely to exist and leads to middle-range ordering. This structure is called cluster-2. The size of such cluster-2 has been estimated to be 2.2 nm for CAAC ?lm and 1.8 nm for NC ?lm using the measured pair distribution function. To gain insights into the structural features of IGZO ?lms, realistic atomic-scale models were obtained to ?t not only the ordinary interference function of grazing incidence X-ray scattering but also the environmental interference function of the anomalous X-ray scattering (AXS) with Zn-absorption edge using reverse Monte Carlo (RMC) simulation. (5) The resultant models indicated the complex and irregular atomic arrangements of two types of IGZO ?lms, which are well characterized by nanometer-sized crystalline clusters. This characteristic feature may be referred to as crystalline-cluster-composite (triple C) structure.
关键词： anomalous X-ray scattering,nanometer-sized crystalline clusters,IGZO ?lm,grazing incidence X-ray scattering,reverse Monte Carlo (RMC) simulation
更新于2025-09-09 09:28:46
-
Perspectives of the Friction Mechanism of Hydrogenated Diamond-Like Carbon Film in Air by Varying Sliding Velocity
摘要： The purpose of the present work is to probe the friction mechanism of hydrogenated diamond-like carbon (H-DLC) ?lm in air by varying sliding velocity (25–1000 mm/s). Friction tests of Al2O3 ball against H-DLC ?lm were conducted with a rotational ball-on-disk tribometer. As the sliding velocity increases, both the friction coef?cient and the surface wear of H-DLC ?lm decrease, reach the minimum values, and then increase in the high sliding velocity region. Based on the observed results, three main friction mechanisms of H-DLC ?lm—namely graphitization mechanism, transfer layer mechanism, and passivation mechanism—are discussed. Raman analysis indicates that the graphitization of worn surface on the H-DLC ?lm has a negligible contribution to the variation of the friction coef?cient and the surface wear. The origin of the sliding velocity dependence is due to the synergistic interaction between the graphitized transfer layer formation and the surface passivation. The present study will not only enrich the understanding of friction mechanism of H-DLC ?lms in air, but will also help to promote their practical engineering applications.
关键词： transfer layer,sliding velocity,surface passivation,diamond-like carbon ?lm,friction mechanism
更新于2025-09-09 09:28:46
-
Fabrication of Ferromagnetic Co–MgF <sub/>2</sub> Granular Film With High Transmittance and Large Faraday Effect for Optical Magnetic Field Sensor
摘要： In the magneto-optical devices and sensors using the Faraday effect, maintaining the transmitted light intensity of a Faraday element is a key issue. A granular ?lm with ferromagnetic ?ne metals dispersed in an insulator matrix has been expected to have both high transmittance and large Faraday effect. In this paper, we fabricated the Co–MgF2 granular ?lm prepared by co-evaporation and investigated the effect of substrate heating temperature during co-evaporation and post-annealing on the transmittance and the Faraday rotation of the granular ?lm. The Co–MgF2 granular ?lm deposited at high substrate temperature was exhibited like a ferromagnetic behavior and high transmittance. Also, we found that the ?gure of merit [deg./dB], which was de?ned as a ratio of a Faraday rotation angle and decay of the transmitted light, was improved by post-annealing.
关键词： Faraday effect,Co-evaporation,granular ?lm,optical magnetic ?eld sensor
更新于2025-09-09 09:28:46
-
[Lecture Notes in Computer Science] Neural Information Processing Volume 11307 (25th International Conference, ICONIP 2018, Siem Reap, Cambodia, December 13–16, 2018, Proceedings, Part VII) || Hopfield Neural Network with Double-Layer Amorphous Metal-Oxide Semiconductor Thin-Film Devices as Crosspoint-Type Synapse Elements and Working Confirmation of Letter Recognition
摘要： Arti?cial intelligences are essential concepts in smart societies, and neural networks are typical schemes that imitate human brains. However, the neural networks are conventionally realized using complicated software and high-performance hardware, and the machine size and power consumption are huge. On the other hand, neuromorphic systems are composed solely of optimized hardware, and the machine size and power consumption can be reduced. Therefore, we are investigating neuromorphic systems especially with amorphous metal-oxide semiconductor (AOS) thin-?lm devices. In this study, we have developed a Hop?eld neural network with double-layer AOS thin-?lm devices as crosspoint-type synapse elements. Here, we propose modi?ed Hebbian learning done locally without extra control circuits, where the conductance deterioration of the crosspoint-type synapse elements can be employed as synaptic plasticity. In order to validate the fundamental operation of the neuromorphic system, ?rst, double-layer AOS thin-?lm devices as crosspoint-type synapse elements are actually fabricated, and it is found that the electric current continuously decreases along the bias time. Next, a Hop?eld neural network is really assembled using a ?eld-programmable gate array (FPGA) chip and the double-layer AOS thin-?lm devices, and it is con?rmed that a necessary function of the letter recognition is obtained after learning process. Once the fundamental operations are con?rmed, more advanced functions will be obtained by scaling up the devices and circuits. Therefore, it is expected the neuromorphic systems can be three-dimensional (3D) large-scale integration (LSI) chip, the machine size can be compact, power consumption can be low, and various functions of human brains will be obtained. What has been developed in this study will be the sole solution to realize them.
关键词： Neural network,Hop?eld neural network,Letter recognition,Arti?cial intelligence,Crosspoint-type synapse elements,Double-layer amorphous metal-oxide semiconductor (AOS) thin-?lm device,Modi?ed hebbian learning
更新于2025-09-09 09:28:46