Microstructure of sputter deposited Ni-Sb ohmic contacts on GaAs

1989 ◽  
Vol 47 ◽  
pp. 450-451
Author(s):  
S. Yegnasubramanian ◽  
V.C. Kannan ◽  
R. Dutto ◽  
P.J. Sakach
Keyword(s):  
High Performance ◽  
Ohmic Contacts ◽  
Surface Defects ◽  
Pure Metal ◽  
Device Fabrication ◽  
Native Oxide ◽  
Metal Thin Films ◽  
Recent Developments ◽  
Different Temperatures ◽  
Sputter Deposited

Recent developments in the fabrication of high performance GaAs devices impose crucial requirements of low resistance ohmic contacts with excellent contact properties such as, thermal stability, contact resistivity, contact depth, Schottky barrier height etc. The nature of the interface plays an important role in the stability of the contacts due to problems associated with interdiffusion and compound formation at the interface during device fabrication. Contacts of pure metal thin films on GaAs are not desirable due to the presence of the native oxide and surface defects at the interface. Nickel has been used as a contact metal on GaAs and has been found to be reactive at low temperatures. Formation Of Ni2 GaAs at 200 - 350C is reported and is found to grow epitaxially on (001) and on (111) GaAs, but is shown to be unstable at 450C. This paper reports the investigations carried out to understand the microstructure, nature of the interface and composition of sputter deposited and annealed (at different temperatures) Ni-Sb ohmic contacts on GaAs by TEM. Attempts were made to correlate the electrical properties of the films such as the sheet resistance and contact resistance, with the microstructure. The observations are corroborated by Scanning Auger Microprobe (SAM) investigations.

Ultrathin Tantalum Pent-Oxide Films for Ulsi Gate Dielectrics

1999 ◽  
Vol 567 ◽  
Author(s):  
Yasushiro Nishioka
Keyword(s):  
Dielectric Constant ◽  
Film Thickness ◽  
High Performance ◽  
Gate Dielectrics ◽  
Gate Insulator ◽  
Process Window ◽  
Weak Spot ◽  
Recent Developments ◽  
Sputter Deposited ◽  
High Dielectric

ABSTRACTUltrathin tantalum pent-oxide (Ta2O5) films with a high dielectric constant over 20 and which are thinner than 10 nm have been extensively studied to realize small area capacitors for memories and high performance MOSFETs. The author and his colleagues started working on ultrathin Ta2O5 films with an equivalent oxide film thickness less than 4 nm for small capacitors for bipolar memories and DRAMS in 1984, and investigated extensively the effects of dry oxygen annealing of sputter-deposited thin Ta2O5 films on Si. We found that there was a process window (dry O2, 800 °C) where defects causing initial and latent breakdown were significantly reduced and where at the same time the reduction in the capacitance inevitably caused by the growth of interfacial SiO2 is kept small. This dry O2 annealing has been widely used for many years due to its effectiveness. This treatment was called “weak spot oxidation.” The interfacial SiO2, with a smaller dielectric constant of 3.9, underneath the Ta2O5 films causes a reduction of the capacitance and an increase of the equivalent film thickness. Annealing of the films after deposition and suppression of the interfacial SiO2 growth are the keys to realizing high performance and reliable Ta2O5 capacitors and gate insulators. In this paper, these fundamental processes are described, along with more recent developments of Ta2O5 thin film technologies, and the potential of the Ta2O5 films as an alternative for a future ULSI gate insulator are also discussed.

What Can Digitization Do For Formulated Product Innovation and Development

2020 ◽  
Author(s):  
James McDonagh ◽  
William Swope ◽  
Richard L. Anderson ◽  
Michael Johnston ◽  
David J. Bray
Keyword(s):  
High Performance ◽  
Quality Data ◽  
High Quality Data ◽  
Base Level ◽  
Hybrid Approaches ◽  
Digital Ecosystem ◽  
Recent Developments ◽  
Chemical Simulation ◽  
High Level ◽  
Physical And Chemical

Digitization offers significant opportunities for the formulated product industry to transform the way it works and develop new methods of business. R&D is one area of operation that is challenging to take advantage of these technologies due to its high level of domain specialisation and creativity but the benefits could be significant. Recent developments of base level technologies such as artificial intelligence (AI)/machine learning (ML), robotics and high performance computing (HPC), to name a few, present disruptive and transformative technologies which could offer new insights, discovery methods and enhanced chemical control when combined in a digital ecosystem of connectivity, distributive services and decentralisation. At the fundamental level, research in these technologies has shown that new physical and chemical insights can be gained, which in turn can augment experimental R&D approaches through physics-based chemical simulation, data driven models and hybrid approaches. In all of these cases, high quality data is required to build and validate models in addition to the skills and expertise to exploit such methods. In this article we give an overview of some of the digital technology demonstrators we have developed for formulated product R&D. We discuss the challenges in building and deploying these demonstrators.<br>

Graphene Oxide and Its Derivatives: Their Synthesis and Use in Organic Synthesis

2019 ◽  
Vol 23 (2) ◽  
pp. 188-204 ◽  
Author(s):  
Xiangjun Peng ◽  
Xianyun Xu ◽  
Fujiang Huang ◽  
Qian Liu ◽  
Liangxian Liu
Keyword(s):  
Graphene Oxide ◽  
Carbon Materials ◽  
Device Fabrication ◽  
Organic Reactions ◽  
Bond Forming ◽  
Bond Forming Reactions ◽  
Modern Physics ◽  
Recent Developments ◽  
Optical And Mechanical Properties ◽  
Nitrogen Double Bond

Since Geim and co-workers reported their groundbreaking experiments on graphene, research on graphene oxide (GO) and its derivatives has greatly influenced the field of modern physics, chemistry, device fabrication, material science, and nanotechnology. The unique structure and fascinating properties of these carbon materials can be ascribed to their eminent chemical, electronic, electrochemical, optical, and mechanical properties of GO and its derivatives, particularly compared to other carbon allotropes. The present Review aims to provide an overview on the recent developments in the preparation of GO and its derivatives and their applications in organic reactions. We will first outline the synthesis of GO and its derivatives. Then, we will discuss the major sections about their application as stoichiometric and catalytic oxidants in organic reactions, a particular emphasis on the carbon-carbon, carbon-oxygen, and carbon-nitrogen single bond-forming reactions, as well as carbon-oxygen and carbon-nitrogen double bond-forming reactions. Simultaneously, this Review also describes briefly transition metal supported on GO or its derivatives as a catalyst for organic reaction. Lastly, we will present an outlook of potential areas where GO and its derivatives may be expected to find utility or opportunity for further growth and study.

scholarly journals Effect of Growth Temperature on the Characteristics of CsPbI3-Quantum Dots Doped Perovskite Film

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4439
Author(s):  
Shui-Yang Lien ◽  
Yu-Hao Chen ◽  
Wen-Ray Chen ◽  
Chuan-Hsi Liu ◽  
Chien-Jung Huang
Keyword(s):  
Thin Films ◽  
Thermal Stability ◽  
Quantum Dots ◽  
Quantum Dot ◽  
Growth Temperature ◽  
Electron Mobility ◽  
Surface Defects ◽  
Different Temperatures ◽  
Pb Doping ◽  
Pristine Film

In this study, adding CsPbI3 quantum dots to organic perovskite methylamine lead triiodide (CH3NH3PbI3) to form a doped perovskite film filmed by different temperatures was found to effectively reduce the formation of unsaturated metal Pb. Doping a small amount of CsPbI3 quantum dots could enhance thermal stability and improve surface defects. The electron mobility of the doped film was 2.5 times higher than the pristine film. This was a major breakthrough for inorganic quantum dot doped organic perovskite thin films.

scholarly journals Can artificially selected phenotypes influence a component of field fitness? Thermal selection and fly performance under thermal extremes

2006 ◽  
Vol 274 (1611) ◽  
pp. 771-778 ◽  
Author(s):  
Torsten Nygaard Kristensen ◽  
Volker Loeschcke ◽  
Ary A Hoffmann
Keyword(s):  
High Performance ◽  
Quantitative Traits ◽  
Genetic Basis ◽  
Selected Lines ◽  
Resistant Lines ◽  
Correlated Patterns ◽  
Different Temperatures ◽  
Evolutionary Trajectories ◽  
Low Performance ◽  
Selected Traits

Artificially selected lines are widely used to investigate the genetic basis of quantitative traits and make inferences about evolutionary trajectories. Yet, the relevance of selected traits to field fitness is rarely tested. Here, we assess the relevance of thermal stress resistance artificially selected in the laboratory to one component of field fitness by investigating the likelihood of adult Drosophila melanogaster reaching food bait under different temperatures. Lines resistant to heat reached the bait more often than controls under hot and cold conditions, but less often at intermediate temperatures, suggesting a fitness cost of increased heat resistance but not at temperature extremes. Cold-resistant lines were more common at baits than controls under cold as well as hot field conditions, and there was no cost at intermediate temperatures. One of the replicate heat-resistant lines was caught less often than the others under hot conditions. Direct and correlated patterns of responses in laboratory tests did not fully predict the low performance of the heat selected lines at intermediate temperatures, nor the high performance of the cold selected lines under hot conditions. Therefore, lines selected artificially not only behaved partly as expected based on laboratory assays but also evolved patterns only evident in the field releases.

Low-resistance Cr/Al Ohmic contacts to N-polar n-type GaN for high-performance vertical light-emitting diodes

2012 ◽  
Vol 12 (1) ◽  
pp. 225-227 ◽  
Author(s):  
Joon-Woo Jeon ◽  
Sang Youl Lee ◽  
June O. Song ◽  
Tae-Yeon Seong
Keyword(s):  
High Performance ◽  
Ohmic Contacts ◽  
Light Emitting Diodes ◽  
Light Emitting ◽  
Low Resistance

Molecular materials for micro-electronics

2000 ◽  
Vol 78 (3) ◽  
pp. 231-241 ◽  
Author(s):  
M D'Iorio
Keyword(s):  
High Performance ◽  
Organic Materials ◽  
Coming Of Age ◽  
Polymeric Materials ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Plastic Electronics ◽  
Organic Light ◽  
Recent Developments

Molecular organic materials have had an illustrious past but the ability to deposit these as homogeneous thin films has rejuvenated the field and led to organic light-emitting diodes (OLEDs) and the development of an increasing number of high-performance polymers for nonlinear and electronic applications. Whereas the use of organic materials in micro-electronics was restricted to photoresists for patterning purposes, polymeric materials are coming of age as metallic interconnects, flexible substrates, insulators, and semiconductors in all-plastic electronics. The focus of this topical review will be on organic light-emitting devices with a discussion of the most recent developments in electronic devices.PACS Nos.: 85.60Jb, 78.60Fi, 78.55Kz, 78.66Qn, 73.61Ph, 72.80Le

Solar-Driven Sorption Chillers for Residential Space Cooling: A Review of Recent Developments and Possible Applications in Canada

2015 ◽  
Author(s):  
Daniel Bowie ◽  
Cynthia A. Cruickshank
Keyword(s):  
High Performance ◽  
Energy Use ◽  
Peak Load ◽  
Internal Heat ◽  
Electricity Grid ◽  
Residential Sector ◽  
Absorption Chillers ◽  
Space Cooling ◽  
Recent Developments ◽  
Advanced Cycles

Energy use for space cooling has increased by 156% from 1990 to 2010 in the Canadian residential sector. In many parts of the country, the increasing use of electrically driven air-conditioners has begun to shift the peak load on the electricity grid from the coldest days of winter to the hottest days of summer. Many of Canada’s major electric utilities providers rely on fossil fuels to generate the additional capacity needed to meet the peak demand, resulting in significant greenhouse gas emissions. Solar-driven sorption chillers remain one of the possible solutions for shaving the peak loads experienced by the electricity grid. This paper presents a review of the recent developments in the research of adsorption and absorption chillers, as well as a comparison of the two technologies based on the latest published experimental results found in the literature. Adsorption chillers continue to evolve in their design, including the use of new consolidated and composite adsorbents, the integration of coated adsorbers into internal heat exchangers, and newly developed advanced cycles for heat and mass recovery. While the physical design of adsorption chillers continues to be advanced, the development of absorption chillers for solar cooling applications has largely been focused on optimizing the system as a whole through improved control strategies and the implementation of newly developed high performance solar collectors. Finally, the paper aims to assess the current state of development of solar-driven sorption chillers to provide insight into their applicability in the Canadian residential sector, as well as the remaining challenges facing this technology.

Sign in / Sign up

Export Citation Format

Share Document