Physical-Chemical Evolution of Hf-aluminates upon Thermal Treatments

2003 ◽  
Vol 765 ◽  
Author(s):  
B. Crivelli ◽  
M. Alessandri ◽  
S. Alberici ◽  
D. Brazzelli ◽  
A. C. Elbaz ◽  
...  
Keyword(s):  
Orthorhombic Phase ◽  
Interface Layer ◽  
Film Structure ◽  
Thermal Treatments ◽  
Tem Analysis ◽  
K Value ◽  
Physical Chemical ◽  
High K ◽  
Post Deposition ◽  
Limited Oxygen

AbstractThis study presents an investigation on physical-chemical stability of (HfO2)x(Al2O3 )1-x alloys upon prolonged post-deposition annealings. Two different Hf-aluminates were deposited by ALCVDTM, containing 34% and 74% Al2O3 mol% respectively. Post-deposition annealings (PDA) were carried out in O2 or N2 atmosphere, at 850°C and 900°C for 30 minutes. Interfacial layer (IL) increase after PDA was detected on all the samples, but with small differences between N2 and O2 treatments. Stack composition was characterized by means of XRR, XRF, RBS and TOF-SIMS. Growth of interface layer was justified by limited oxygen incorporation from external ambient. Silicon diffusion from the substrate into high-k material and aluminum/hafnium redistribution were observed and associated to annealing temperature. XRD and planar TEM analysis evidenced first grain formation and then, in the case of Hf-rich samples, almost complete crystallization. Overall, Hf-aluminates were found to remain XRD amorphous during high temperature prolonged treatments up to 900°C for 74% and 850°C for 34% alloys respectively. Differently from HfO2, (HfO2)0.66(Al2O3 )0.34 alloy was observed to crystallized in orthorhombic phase. Hf-aluminates were also electrically characterized by means of C(V) and I(V) measurements on basic capacitors. Variations in material electrical properties were found consistent with change in physical-chemical film structure. Increase in k value up to 30 was observed on Hf-rich samples crystallized in orthorhombic phase.

Physical-Chemical Evolution upon Thermal Treatments of Al2O3, HfO2 and Al/Hf Composite Materials Deposited by ALCVD™

2002 ◽  
Vol 745 ◽  
Author(s):  
B. Crivelli ◽  
M. Alessandri ◽  
S. Alberici ◽  
F. Cazzaniga ◽  
D. Dekadjevi ◽  
...  
Keyword(s):  
Composite Materials ◽  
Chemical Evolution ◽  
Systematic Investigation ◽  
Film Structure ◽  
Thermal Treatments ◽  
Electrical Measurements ◽  
Physical Chemical ◽  
Treatment Conditions ◽  
High K ◽  
High K Materials

ABSTRACTThis paper presents a systematic investigation of thermal stability of high-k materials deposited on RCA cleaned wafers by ALCVD™ in an ASM Pulsar™ 2000 reactor. Physical-chemical evolution of Al2O3, HfO2 and Al/Hf composite materials (nanolaminate and aluminates) was studied considering two types of thermal treatments: quenched vacuum anneals from 300°C to 900°C and furnace atmospheric processes in N2 or O2 at 850°C and 900°C. Material crystallization and changes in film structure were studied by means of TEM, XRD, XRR, XRF, RBS and TOF-SIMS. Non-contact electrical measurements were used to detect modification in EOT and fixed charge. Al2O3 was found still amorphous at 900°C. Not so for HfO2 that crystallized in monoclinic phase at a temperature between 300–400°C. Crystallization temperature and possible phase separation of Al/Hf composite materials were found to be a function of Al2O3 content and film type. In most of these samples, however, a chemical evolution was detected in addition to the above reported crystallization phenomena. All the achieved results demonstrate that depending on thermal treatment conditions, ALCVD™ high-k stability does not only concern phase transition effects but also a transformation of the “SiO2/high-k” system into “doped-SiO2/silicate” stack.

Crystallization Behavior of Hf-rich Aluminates and Influence on Film Dielectric Properties

2004 ◽  
Vol 811 ◽  
Author(s):  
M. Climent ◽  
B. Crivelli ◽  
G. Righini ◽  
S. Alberici ◽  
M. Alessandri ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Thermal Evolution ◽  
Orthorhombic Phase ◽  
Interface Layer ◽  
Thermal Treatments ◽  
Prolonged Annealing ◽  
Increasing Trend ◽  
Sequential Mode ◽  
Film Dielectric ◽  
Post Deposition

ABSTRACTIn this study, the investigation of crystallization behaviour of Hf-rich aluminate is presented. Different alloys were deposited by ALCVD™ with composition ranging between 16 and 47 Al2O3 mol%. Post-deposition annealings were carried out in single or sequential mode using purified N2 at atmospheric pressure. Process temperature and time were varied from 700°C to 900°C and from 1' to 30' respectively. Upon these conditions, film thermal evolution was observed without any relevant increasing of in interface layer and any change in material composition. Measurements on 20 Al2O3 mol% films evidenced that thermal treatments up to 800°C promoted initial shrinking in thickness and material densification. Above 900°C, all considered aluminates were found to crystallize in orthorhombic phase maintaining original alloy composition. The higher the alumina content, the lower the grain size, the higher the crystallites density. Stability of orthorhombic crystalline structure was demonstrated upon single prolonged annealing up to 30' and upon sequential processes. In correspondence with film crystallization, enhancement of dielectric constant was detected with an increasing trend upon hafnia content. For 20 Al2O3 mol% aluminate, change in k form 19 to 40-45 was observed together with limited degradation in conduction and breakdown characteristics.

Engineering the nm-thick Interface Layer Formed Between a High-k Film and Silicon

2004 ◽  
Vol 811 ◽  
Author(s):  
J. Lu ◽  
J. -Y. Tewg ◽  
Y. Kuo
Keyword(s):  
Charge Density ◽  
Layer Structure ◽  
Charge Trapping ◽  
Dielectric Strength ◽  
Interface Layer ◽  
Fixed Charge ◽  
K Value ◽  
Fixed Charge Density ◽  
Hafnium Nitride ◽  
High K

ABSTRACTThe interface layer between thin sputter-deposited tantalum oxide (TaOx) high-k film and silicon substrate was engineered with the Hf doping method and the insertion of a thin 5Å TaNx interface. The following results have been obtained: 1) the Hf dopant in the TaOx film was involved in the interface formation process, e.g., forming a new, thinner high-k HfSixOy interface layer rather than the SiOx layer, 2) when the TaNx interface was inserted, the interface layer composition was even more complicated, e.g., including TaOxNy and HfSixOy structures. No hafnium nitride or oxynitride was detected, 3) the interface layer structure was changed, e.g., from single-zone to multi-zone with different compositions, 4) when a low concentration of Hf existed in the TaOx film, the high-k dielectric properties, such as the k value, fixed charge density, dielectric strength, were improved, and 5) when the thin TaNx interface layer was inserted, the above electric properties were further improved. However, the fixed charge density and interface states were increased due to the insertion of the TaNx interface layer. These results were contributed by factors such as the charge-trapping characteristics in the interface layer and the some damage repairing mechanisms. In summary, this research proved that the high-k film's interface layer and bulk properties could be were improved with the doping process as well as the insertion of an ultra-thin TaNx interface film.

Scalability of MOCVD-deposited Hafnium Oxide

2003 ◽  
Vol 765 ◽  
Author(s):  
S. Van Elshocht ◽  
R. Carter ◽  
M. Caymax ◽  
M. Claes ◽  
T. Conard ◽  
...  
Keyword(s):  
Hafnium Oxide ◽  
Interfacial Layer ◽  
Gate Dielectric ◽  
Deposition Process ◽  
Oxide Thickness ◽  
Process Conditions ◽  
Primary Concern ◽  
Gate Electrode ◽  
K Value ◽  
High K

AbstractBecause of aggressive downscaling to increase transistor performance, the physical thickness of the SiO2 gate dielectric is rapidly approaching the limit where it will only consist of a few atomic layers. As a consequence, this will result in very high leakage currents due to direct tunneling. To allow further scaling, materials with a k-value higher than SiO2 (“high-k materials”) are explored, such that the thickness of the dielectric can be increased without degrading performance.Based on our experimental results, we discuss the potential of MOCVD-deposited HfO2 to scale to (sub)-1-nm EOTs (Equivalent Oxide Thickness). A primary concern is the interfacial layer that is formed between the Si and the HfO2, during the MOCVD deposition process, for both H-passivated and SiO2-like starting surfaces. This interfacial layer will, because of its lower k-value, significantly contribute to the EOT and reduce the benefit of the high-k material. In addition, we have experienced serious issues integrating HfO2 with a polySi gate electrode at the top interface depending on the process conditions of polySi deposition and activation anneal used. Furthermore, we have determined, based on a thickness series, the k-value for HfO2 deposited at various temperatures and found that the k-value of the HfO2 depends upon the gate electrode deposited on top (polySi or TiN).Based on our observations, the combination of MOCVD HfO2 with a polySi gate electrode will not be able to scale below the 1-nm EOT marker. The use of a metal gate however, does show promise to scale down to very low EOT values.

Process and Manufacturing Challenges for High-K Gate Stack Systems

1999 ◽  
Vol 567 ◽  
Author(s):  
M.C. Gilmer ◽  
T-Y Luo ◽  
H.R. Huff ◽  
M.D. Jackson ◽  
S. Kim ◽  
...  
Keyword(s):  
Silicon Surface ◽  
Gate Dielectrics ◽  
Electrical Characterization ◽  
Metal Electrode ◽  
Significant Variable ◽  
Tem Analysis ◽  
Physical Mechanisms ◽  
High K ◽  
Commercial Equipment

ABSTRACTA design-of-experiments methodology was implemented to assess the commercial equipment viability to fabricate the high-K dielectrics Ta2O5, TiO2 and BST (70/30 and 50/50 compositions) for use as gate dielectrics. The high-K dielectrics were annealed in 100% or 10% O2 for different times and temperatures in conjunction with a previously prepared NH3 nitrided or 14N implanted silicon surface. Five metal electrode configurations—Ta, TaN, W, WN and TiN—were concurrently examined. Three additional silicon surface configurations were explored in conjunction with a more in-depth set of time and temperature anneals for Ta2O5. Electrical characterization of capacitors fabricated with the above high-K gate dielectrics, as well as SIMS and TEM analysis, indicate that the post high-K deposition annealing temperature was the most significant variable impacting the leakage current density, although there was minimal influence on the capacitance. Further studies are required, however, to clarify the physical mechanisms underlying the electrical data presented.

Metabolism of the Black Snake Embryo

1953 ◽  
Vol 30 (4) ◽  
pp. 492-501 ◽  
Author(s):  
HUGH CLARK
Keyword(s):  
Energy Source ◽  
Uric Acid ◽  
Acid Synthesis ◽  
K Value ◽  
Embryonic Tissues ◽  
Hatching Time ◽  
Urea Content ◽  
Foetal Liver ◽  
Liver And Kidney ◽  
Post Deposition

1. Post-deposition growth of the black snake embryo is characterized by k values as follows: days 1-11, 0.46; days 11-34, 0.057; days 34-67, 0.039. 2. Total excreted nitrogen is 12.55 mg. occurring successively in development as ammonia, urea and uric acid; k value of total nitrogen production is 0.062, days 11-67, which in comparison with those of growth during this period suggest that stored protein is an energy source during a large part of development. 3. Urea is excreted into the albumen which is the principal storage reservoir and into the yolk; that which is excreted into the yolk is reabsorbed after the 45th day and re-deposited in the albumen as urea, and is in part (22%) converted to uric acid. 4. Concentration of urea in the yolk and yolk-sac continues to increase at the same rate after the 11th day (k = 0.024), although the actual amount declines after the 45th day; concentration in the embryonic tissues increases to the 58th day, then decreases sharply to hatching time; concentration in the albumen increases throughout development, reaching a concentration of approximately 500 mg.%. 5. Uric acid synthesis is believed to be preceded by urea formation, and the presence of urease in the foetal liver and kidney suggest that the urea is hydrolysed to ammonia which is then incorporated into uric acid. Site of the transformation is uncertain, though the early and persistent localization of uric acid in the chorio-allantoic membrane points to this as the organ of synthesis. Decrease in total urea content is quantitatively identical with increase in uric acid. 6. The significance of these findings in relation to development of the vertebrate cleidoic egg is discussed.

Data normalization for training and analysis of the MaskRCNN model using the k-means method for computer vision of smart refrigerator

2021 ◽  
Vol 4 ◽  
pp. 74-80
Author(s):  
M. G. Dorrer ◽  
◽  
A.E. Alekhina ◽  
Keyword(s):  
Computer Vision ◽  
Semantic Segmentation ◽  
Correct Choice ◽  
Training Sample ◽  
Artificial Vision ◽  
K Value ◽  
High K ◽  
Real World Datasets ◽  
Segmentation Problem

This paper proposes using the k-means method for the controlled adjustment of the training sample for semantic image segmentation in the artificial vision of a smart refrigerator. To solve this problem, a new two-stage architecture for computer vision is proposed. In the proposed architecture, various sets of settings for optimizing the contrast of images are used to classify pixels according to their belonging to fragments of the studied image. Extensive experimental evaluation shows that the proposed method has critical advantages over existing work. Firstly, the obtained pixel classes can be directly clustered into semantic groups using k-means. Secondly, the method can be used for additional training of artificial intelligence in solving the semantic segmentation problem. The developers propose an approach to the correct choice of the number k of centroids to obtain good quality clusters, which is difficult to determine at a high k value. To overcome the problem of initializing the k-means method, an incremental k-means clustering method is proposed, which improves the quality of clusters to reduce the sum of squared errors. Comprehensive experiments have been carried out compared to the traditional k-means algorithm and its new versions to evaluate the performance of the proposed method on synthetically generated datasets and some real-world datasets.

scholarly journals Nb2O5 and Ti-Doped Nb2O5 Charge Trapping Nano-Layers Applied in Flash Memory

Nanomaterials ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 799 ◽  
Author(s):  
Jer Wang ◽  
Chyuan Kao ◽  
Chien Wu ◽  
Chun Lin ◽  
Chih Lin
Keyword(s):  
Flash Memory ◽  
Charge Trapping ◽  
Memory Device ◽  
Dielectric Constants ◽  
Oxide Semiconductor ◽  
Flat Band ◽  
Hysteresis Curve ◽  
Band Shift ◽  
K Value ◽  
High K

High-k material charge trapping nano-layers in flash memory applications have faster program/erase speeds and better data retention because of larger conduction band offsets and higher dielectric constants. In addition, Ti-doped high-k materials can improve memory device performance, such as leakage current reduction, k-value enhancement, and breakdown voltage increase. In this study, the structural and electrical properties of different annealing temperatures on the Nb2O5 and Ti-doped Nb2O5(TiNb2O7) materials used as charge-trapping nano-layers in metal-oxide-high k-oxide-semiconductor (MOHOS)-type memory were investigated using X-ray diffraction (XRD) and atomic force microscopy (AFM). Analysis of the C-V hysteresis curve shows that the flat-band shift (∆VFB) window of the TiNb2O7 charge-trapping nano-layer in a memory device can reach as high as 6.06 V. The larger memory window of the TiNb2O7 nano-layer is because of a better electrical and structural performance, compared to the Nb2O5 nano-layer.

scholarly journals Hydrogen Diffusion Coefficient, Hydrogen Solution Coefficient and Hydrogen Permeability of Nb-TiNi Eutectic Alloy

2010 ◽  
Vol 638-642 ◽  
pp. 1131-1136
Author(s):  
Wei Liang Wang ◽  
Kazuhiro Ishikawa ◽  
Kiyoshi Aoki
Keyword(s):  
Diffusion Coefficient ◽  
Hydrogen Absorption ◽  
Hydrogen Diffusion ◽  
Hydrogen Permeability ◽  
K Value ◽  
Hydrogen Flow ◽  
Hydrogen Diffusion Coefficient ◽  
High K ◽  
Pressure Region ◽  
The Difference

In general, hydrogen permeabilityΦ of the alloy membrane is expressed as the product of the hydrogen diffusion coefficient D and the hydrogen solution coefficient K. Therefore, to improve the hydrogen permeability efficiently, the values of K and D should be separately considered. In the present study, hydrogen absorption and permeation behaviors of the Nb19Ti40Ni41 alloy consisting of the eutectic phase are investigated by measuring pressure-composition-isotherm (PCI) and by the hydrogen flow method and compared with those of palladium. The hydrogen absorption in the Nb19Ti40Ni41 alloy does not obey the Sieverts’ law in the pressure region of 0-1.0MPa at 523K, but it shows linear relationship between the difference in the square root of hydrogen pressure and hydrogen content between 0.1 and 0.4MPa. Although the value of D for the Nb19Ti40Ni41 alloy is considerably lower than that of palladium, its high K value enhances the hydrogen permeability Φ. It is suggested that the enhancement of D by microstructural control for Nb19Ti40Ni41 alloy is effective for improvement of Φ.

scholarly journals Peculiarities of time-dependent-dielectric breakdown characteristics of pure and doped Ta2O5 stacks

2013 ◽  
Vol 26 (3) ◽  
pp. 281-296
Author(s):  
E. Atanassova ◽  
A. Paskaleva
Keyword(s):  
Dielectric Breakdown ◽  
Interface Layer ◽  
Time Dependent ◽  
Relative Impact ◽  
Time Dependent Dielectric Breakdown ◽  
Breakdown Mechanism ◽  
Number Of Factors ◽  
High K ◽  
Induced Defects

The effect of both the process-induced defects and the dopant on the time-dependent-dielectric breakdown in Ta2O5 stacks is discussed. The breakdown degradation is analyzed in terms of specific properties of high-k stacks which make their dielectric breakdown mechanism completely different from that of classical SiO2. The relative impact of a number of factors constituting the reliability issues in Ta2O5-based capacitors (trapping in pre-existing traps, stress-induced new traps generation, the presence of interface layer at Si and the role of the dopant) is clarified.

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