scholarly journals Ultra-High Implant Activation Efficiency In GaN Using Novel High Temperature RTP System

1998 ◽  
Vol 512 ◽  
Author(s):  
X. A. Cao ◽  
C. R. Abernathy ◽  
R. K. Singh ◽  
S. J. Pearton ◽  
M. Fu ◽  
...  
Keyword(s):  
Thin Films ◽  
Activation Energy ◽  
High Temperature ◽  
Complete Loss ◽  
Surface Degradation ◽  
Cooling Rates ◽  
Heating And Cooling ◽  
Activation Efficiency ◽  
High Heating

ABSTRACTSi+ implant activation efficiencies above 90%, even at doses of 5×1015 cm−2, have been achieved in GaN by RTP at 1400–1500°C for 10 secs. The annealing system utilizes with MoSi2 heating elements capable of operation up to 1900 °C, producing high heating and cooling rates (up to 100 °C · s−1). Unencapsulated GaN show severe surface pitting at 1300 °C, and complete loss of the film by evaporation at 1400 °C. Dissociation of nitrogen from the surface is found to occur with an approximate activation energy of 3.8 eV for GaN (compared to 4.4 eV for AIN and 3.4 eV for InN). Encapsulation with either rf-magnetron reactively sputtered or MOMBE-grown AIN thin films provide protection against GaN surface degradation up to 1400 °C, where peak electron concentrations of ∼5×1020 cm-3 can be achieved in Si-implanted GaN. SIMS profiling showed little measurable redistribution of Si, suggesting Dsi ≤ 10-13 cm2 · s−1 at 1400 °C. The implant activation efficiency decreases at higher temperatures, which may result from SiGa to SiN site switching and resultant self-compensation.

EBSD Coupled to SEM In Situ Annealing as a Tool to Identify Recrystallization Mechanisms - Application to Zr and Ta Alloys

2012 ◽  
Vol 715-716 ◽  
pp. 486-491
Author(s):  
Nathalie Bozzolo ◽  
S. Jacomet ◽  
M. Houillon ◽  
B. Gaudout ◽  
Roland E. Logé
Keyword(s):  
High Temperature ◽  
Short Duration ◽  
Microstructure Evolution ◽  
Room Temperature ◽  
Heat Treatments ◽  
Cooling Rates ◽  
Heating And Cooling ◽  
Orientation Mapping ◽  
High Heating

A heating stage as been developed to perform in-situ annealing in a SEM equipped with an EBSD system in order to study recrystallization mechanisms. High temperature treatments could then be performed inside the SEM, up to 1180°C and with high heating-and cooling-rates (~100°C.s-1). Samples were cooled down to room temperature to perform EBSD orientation mapping in between successive short-duration heat-treatments. Microstructure evolution snapshots obtained this way are presented in this paper to show recrystallization in Zircaloy4 and in pure tantalum.

A new DSC for high heating and cooling rates measurements

1988 ◽  
Vol 134 ◽  
pp. 389-394 ◽  
Author(s):  
Ken-Ichi Hirano ◽  
Tamio Ohshima ◽  
Hiroshi Okamoto ◽  
Ryozo Kato ◽  
Akikazu Maesono
Keyword(s):  
Cooling Rates ◽  
Heating And Cooling ◽  
High Heating

A New 1000°C Double Tilt Stage for the Hitachi 650 kV Microscope

1974 ◽  
Vol 32 ◽  
pp. 442-443
Author(s):  
W. Worthington ◽  
T. Kosel ◽  
R. Sinclair
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
High Temperature ◽  
Electric Current ◽  
Heating Element ◽  
Design Criteria ◽  
Original Design ◽  
Cooling Rates ◽  
Heating And Cooling ◽  
Specimen Holder

A new 1000°C specimen holder has been developed for the Hu-650 electron microscope and is interchangeable with other holders for the recently designed orthagonal drive tilting stage. The requirements for the high temperature device were as follows: 1. An orthogonal double-tilt stage with all original design criteria maintained(1). 2. Capability of heating standard (3mm. dia.) metallurgical specimens to 1000°C. 3. Geometry and materials should be such that stage and microscope components shall not be damaged by heat from the specimen holder. 4. The electric current to the heating element shall impart a minimum effect upon the microscope electron beam. 5. Heating and cooling rates to be as rapid as possible.

Fabrication of Ceramic High Temperature Microsystems

2011 ◽  
Author(s):  
Benjamin Kellie ◽  
Shaurya Prakash
Keyword(s):  
High Temperature ◽  
Weight Ratio ◽  
Polymer Binder ◽  
Binder Content ◽  
Poly Vinyl Alcohol ◽  
Heat Output ◽  
Polymeric Binder ◽  
Green Body ◽  
Cooling Rates ◽  
Heating And Cooling

This paper reports on recent advances in fabricating alumina-based ceramic microcombustors for applications in high temperature microsystems. We have fabricated alumina structures with critical dimensions on the order of 1 mm or less by using a gel-casting approach with poly(vinyl) alcohol (PVA) as a non-toxic polymeric binder. Polymer binder content, alumina weight ratio, and thermal cycling were varied systematically to develop microcombustors that can sustain stable flames in a spiral configuration allowing for better mixing of fuel and oxidizer streams for a more uniform heat output. The polymer binder and cross-linker content varied between 10 and 20% (w/v to DI water) and 50 and 100% (w/w to PVA) respectively to obtain an optimal binder content. The weight ratio of alumina (w/w 30–50%) in the binder solution was evaluated with 1.1 micron particles to observe the effect on the green body density. The green body was then fired in a high temperature furnace in air to burn-out the polymeric binder and sinter the ceramic. Heating and cooling rates, maximum operation temperature, and dwell times were evaluated to obtain high density ceramic structures with 50% or higher alumina content. Thermal stress and heating and cooling rates appear to be major parameters to control in order to obtain high-quality microcombustors.

scholarly journals Experimental setup for high-temperature in situ studies of crystallization of thin films with atmosphere control

2020 ◽  
Vol 27 (5) ◽  
pp. 1209-1217 ◽  
Author(s):  
Anders Bank Blichfeld ◽  
Kristine Bakken ◽  
Dmitry Chernyshov ◽  
Julia Glaum ◽  
Tor Grande ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
High Temperature ◽  
High Heating Rate ◽  
Heating Rates ◽  
Maximum Information ◽  
High Heating ◽  
Atmosphere Control ◽  
Sample Environment

Understanding the crystallization process for chemical solution deposition (CSD) processed thin films is key in designing the fabrication strategy for obtaining high-quality devices. Here, an in situ sample environment is presented for studying the crystallization of CSD processed thin films under typical processing parameters using near-grazing-incidence synchrotron X-ray diffraction. Typically, the pyrolysis is performed in a rapid thermal processing (RTP) unit, where high heating rates, high temperatures and atmosphere control are the main control parameters. The presented in situ setup can reach heating rates of 20°C s−1 and sample surface temperatures of 1000°C, comparable with commercial RTP units. Three examples for lead-free ferroelectric thin films are presented to show the potential of the new experimental set-up: high temperature, for crystallization of highly textured Sr0.4Ba0.6Nb2O6 on a SrTiO3 (001) substrate, high heating rate, revealing polycrystalline BaTiO3, and atmosphere control with 25% CO2, for crystallization of BaTiO3. The signal is sufficient to study a single deposited layer (≥10 nm for the crystallized film) which then defines the interface between the substrate and thin film for the following layers. A protocol for processing the data is developed to account for a thermal shift of the entire setup, including the sample, to allow extraction of maximum information from the refinement, e.g. texture. The simplicity of the sample environment allows for the future development of even more advanced measurements during thin-film processing under non-ambient conditions.

Cooling and Heating Characteristics of Ti-Ni Based Shape Memory Alloy Wire Actuators

2007 ◽  
Vol 124-126 ◽  
pp. 1649-1652 ◽  
Author(s):  
Jung Min Nam ◽  
Jae Hwa Lee ◽  
Yun Jung Lee ◽  
Tae Hyun Nam
Keyword(s):  
Cooling Rate ◽  
Heating Rate ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Heating Rates ◽  
Cooling Rates ◽  
Alloy Wire ◽  
Heating And Cooling ◽  
High Heating ◽  
Better Than

Ti-51Ni(at%) and Ti-40Ni-10Cu(at%) alloy wires with diameters of 0.3mm, 0.5mm and 0.7mm were prepared by drawing the alloy ingots fabricated by vacuum induction melting. Heating rates of the wires were investigated by measuring changes in temperatures of them while applying currents in the range of 1 A and 6 A to them and cooling rates were investigated by measuring changes in temperatures of them after cutting currents. Heating rate increased with increasing the amount of current, while cooling rate was kept constant. Both heating rate and cooling rate increased with decreasing diameter of wire. This suggested that high amount of current and small wire diameter were required for high heating and cooling rate. Comparing Ti-50Ni alloy wires with Ti-40Ni-10Cu alloy wires, heating rates of the latter was faster than that of the former, although cooling rates were almost same. This suggested that Ti-40Ni-10Cu alloy wires is better than Ti-50Ni alloy wires for the applications requiring high actuating rates.

Phase Transformations during Laser Processing of Aerospace Metallic Materials

2016 ◽  
Vol 1135 ◽  
pp. 179-201 ◽  
Author(s):  
Milton Sergio Fernandes de Lima
Keyword(s):  
High Temperature ◽  
Phase Transformations ◽  
Metallic Materials ◽  
Laser Materials ◽  
Rapid Phase ◽  
Practical Applications ◽  
Heating And Cooling ◽  
High Heating ◽  
Short Time ◽  
Very High

Phase transformations in laser processed metallic materials usually occur under very high temperature gradients and during a short time. Therefore, laser materials processing has been usually associated to high heating and cooling rates. However, before understanding the temperature evolution of the target, the absorptivity and the optical penetration must be considered. This paper presents some conjectures about the how the metal absorbs the laser radiation and how rapid phase transformations take place. It would be proposed that the interface response functions could be a possible way to understand phase transformations from liquid or high temperature solid solution conditions. Finally, it will be presented some results about laser processed materials of aerospace interest: steels, titanium and aluminium, which will illustrate the practical applications of the theories.

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