Vertical high-speed rotating disk reactors for production scale MOVPE of compound semiconductors

A rotating disk with varying thickness and inhomogeneity, and subjected to a steady, inhomogeneous temperature field is analyzed. To handle the arbitrary profile, the disk is discretized into a series of uniform annular disks possessing constant material properties and then solved by the step-reduction method. Analytic expressions for thermoelastic stresses are given, and based on these results, the formulation is extended to include the calculation of shrink fit, the solving of the inverse problem for equistrength rotating disks, and the computations of plastic stresses and creep at elevated temperatures.

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Quasi-Static Thermal Modeling of Multiscale Sliding Contact for Unlubricated Brush Seal Materials

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4042722 ◽

2019 ◽

Vol 141 (7) ◽

Cited By ~ 1

Author(s):

Qingfeng Xia ◽

David R. H. Gillespie ◽

Andrew K. Owen ◽

Gervas Franceschini

Keyword(s):

Thermal Conductivity ◽

High Speed ◽

Rotating Disk ◽

Contact Temperature ◽

Infinite Length ◽

Rotating Speed ◽

Thermal Anisotropy ◽

Heat Partition ◽

Anisotropic Thermal Conductivity ◽

Wide Range

Prediction of contact temperature between two materials in high-speed rubbing contact is essential to model wear during unlubricated contact. Conventionally, assumptions of either a steady or an annular heat source are used for slow and high speed rotation, respectively. In this paper, a rotating heating source is solved using an in-house finite element method code. This captures the full geometry and rotating speed of the rubbing bodies. Transient heat transfer is modeled quasi-statically, eliminating the need for a transient 3D simulation. This model is shown to be suitable for contact temperature prediction over a wide range of rotating speeds, anisotropic thermal conductivity, and nonuniform thermal boundary conditions. The model calculates heat partition accurately for a thin rotating disk and short pin combination, which cannot be predicted using the existing analytical solutions. The method is validated against ansys mechanical and experimental infrared thermography. Results demonstrate that the annular source assumption significantly underpredicts contact temperature, especially at the rubbing interface. Explicit modeling of a thin disk results in higher heat partition coefficients compared with the commonplace semi-infinite length assumption on both static and rotating components. The thermal anisotropy of tuft-on-disk configurations is evaluated and compared to a uniform pin-on-disk configuration. Despite the effective thermal conductivity (ETC) in the bristle tuft being approximately 1 order of magnitude lower than along the bristle length (treating the bristle pack as a porous medium), its impact on heat partition and contact temperature is shown to be limited.

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Development of a hybrid ozonation biofilm-membrane filatration process for the production of drinking water

Water Science & Technology ◽

10.2166/wst.2005.0643 ◽

2005 ◽

Vol 51 (6-7) ◽

pp. 241-248 ◽

Cited By ~ 4

Author(s):

T. Leiknes ◽

M. Lazarova ◽

H. Ødegaard

Keyword(s):

Drinking Water ◽

Organic Matter ◽

High Speed ◽

Membrane Surface ◽

Drinking Water Treatment ◽

Rotating Disk ◽

Operating Conditions ◽

Operating Modes ◽

High Concentrations ◽

Biomass Separation

Drinking water sources in Norway are characterized by high concentrations of natural organic matter (NOM), low alkalinity and low turbidity. The removal of NOM is therefore a general requirement in producing potable water. Drinking water treatment plants are commonly designed with coagulation direct filtration or NF spiral wound membrane processes. This study has investigated the feasibility and potential of a hybrid process combining ozonation and biofiltration with a rotating disk membrane for treating drinking water with high NOM concentrations. Ozonation will oxidize the NOM content removing colour and form biodegradable organic compounds, which can be removed in biological filters. A constructed water was used in this study which is representative of ozonated NOM-containing water. A rotating membrane disk bioreactor downstream the ozonation process was used to carry out both the biodegradation as well as biomass separation in the same reactor. Maintenance of biodegradation of the organic matter while controlling biofouling of the membrane and acceptable water production rates was the focus in the study. Three operating modes were investigated. Removal of the biodegradable organics was consistent throughout the study indicating that sufficient biomass was maintained in the reactor for all operating conditions tested. Biofouling control was not achieved through shear-induced cleaning by periodically rotating the membrane disks at high speed. By adding a small amount of sponges in the membrane chamber the biofouling could be controlled by mechanical cleaning of the membrane surface during disk rotation. The overall results indicate that the system can favorably be used in an ozonation/biofiltration process by carrying out both biodegradation as well as biomass separation in the same reactor.

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MOVPE growth of II–VI compounds in a vertical reactor with high-speed horizontal rotating disk

Journal of Crystal Growth ◽

10.1016/0022-0248(91)90456-f ◽

1991 ◽

Vol 107 (1-4) ◽

pp. 198-202 ◽

Cited By ~ 9

Author(s):

G.S. Tompa ◽

T. Salagaj ◽

L. Cook ◽

R.A. Stall ◽

C.R. Nelson ◽

...

Keyword(s):

High Speed ◽

Rotating Disk ◽

Movpe Growth

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Fabrication of Nanotips and Microbeams in Antimonide Based Semiconductor Material using Bromine Ion Beam Assisted Etching

MRS Proceedings ◽

10.1557/proc-792-r7.7 ◽

2003 ◽

Vol 792 ◽

Cited By ~ 1

Author(s):

B. Krejca ◽

S.R. Vangala ◽

K. Krishnaswami ◽

R. Kolluru ◽

M. C. Ospina ◽

...

Keyword(s):

High Speed ◽

Mechanical Characteristics ◽

Ion Beam ◽

Compound Semiconductors ◽

Etching Technique ◽

Force Microscopy ◽

Analysis Techniques ◽

Atomic Force ◽

Beam Analysis ◽

Novel Structures

ABSTRACTAntimonide-based compound semiconductors have emerged as the materials of choice for fabricating high-speed low-power electronics and electro-optics for applications requiring miniaturization and portability. In this work Br-IBAE is shown to be an anisotropic antimonide etching technique that is capable of generating novel structures as well as performing standard etching tasks. When etching less than optimally chemical-mechanical polished (111) InSb wafers, sharp-tipped cone structures with tip radii of the order of less than 60 nm are produced. These structures may be ideally suited for the development of field-emission devices, where small tip radii are required for useful emission currents. The anisotropic nature of the IBAE technique allows one to etch channels in the surface at angles up to 70° from perpendicular, making the fabrication of microbeams feasible. Using an angled sample holder, the first etch undercuts the masked beams from one side. The sample is then removed and realigned so as to undercut the beams from the other side. The triangular shaped microbeams are left suspended from either one or both ends. Using a combination of atomic force microscopy and mechanical engineering beam analysis techniques, the elastic parameters of the material can be measured. The microbeams can be aligned along various directions on the surface to investigate anisotropic characteristics. This is particularly important for determining the mechanical characteristics of materials that can only be grown in thin epitaxial layers, such as quaternary antimonide-based compound semiconductors.

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Mechanical, Thermal and Flow Dynamics Issues in Compound Semiconductor MOCVD Reactor Design

MRS Proceedings ◽

10.1557/proc-340-135 ◽

1994 ◽

Vol 340 ◽

Author(s):

A.I. Gurary ◽

G.S. Tompa ◽

K. Moy ◽

P. Zawadzki

Keyword(s):

Quantum Wells ◽

High Speed ◽

Chemical Vapor ◽

Cost Effective ◽

Rotating Disk ◽

Compound Semiconductor ◽

Element Analysis ◽

Long Wavelength ◽

Mocvd Reactor ◽

Reactor Geometry

ABSTRACTIn recent years Metalorganic Chemical Vapor Deposition (MOCVD) becomes a key epitaxial process for a variety of compound semiconductor devices such as: GaAs/AlGaAs lasers, HEMTs, LEDs, photocathodes, solar cells, and MESFETs; InP/InGaAsP long wavelength lasers and detectors; InP/InGaAs quantum wells and detectors, etc. Development of reliable, high throughput equipment is a major task in the implementation of MOCVD into cost-effective manufacturings. We have used Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) software to model thermal, structural, and flow processes for the scaling of EMCORE vertical, high speed rotating disk reactor (RDR) to large dimensions (four 4″ wafers located on 12″ wafer carrier). Flow modeling was used to determine basic reactor geometry and the relation between process parameters such as total reactant flow, temperature, pressure, and rotation speed. Thermal and structural analysis was used to produce a uniform substrate temperature, avoid reactor overheating and decrease thermal stress. Flow and temperature distribution predicted by the modeling were found to be well correlated with experimental results.

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Temperature Measurements Using In Thermocouple In The Mocvd Rotating Disk Reactors

MRS Proceedings ◽

10.1557/proc-406-139 ◽

1995 ◽

Vol 406 ◽

Author(s):

A. I. Gurary ◽

R. A. Stall

Keyword(s):

Process Parameters ◽

Chemical Vapor ◽

Rotating Disk ◽

Temperature Measurements ◽

High Yield ◽

Wafer Temperature ◽

Rotating Disk Reactors ◽

And Control ◽

Measurement And Control ◽

Accuracy And Repeatability

AbstractRotating Disk Reactors used for Metalorganic Chemical Vapor Deposition have evolved into a leading manufacturing technology for several materials, including nitrides, compound semiconductors, metals, and oxides. One of the major issues to be resolved in bringing this technology into routine high yield manufacturing has been precise and repeatable wafer temperature measurement and control. The conventional approach to the rotating wafer temperature measurements by a stationary thermocouple located near the rotating wafer carrier suffers from low accuracy and repeatability. We have implemented a rotating thermocouple with a junction located close to the wafer for the temperature measurements in the MOCVD Rotating Disk Reactor. This approach allowed us to obtain reliable and accurate wafer temperature measurements with minimum dependence upon variable process parameters and to protect the thermocouple from degradation in the aggressive reactor environment. The temperature difference between wafer and thermocouple for the rotating and stationary thermocouple designs as a function of process parameters will be discussed.

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