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Air Force Institute of Technology

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Articles 4261 - 4290 of 5699

Full-Text Articles in Engineering

Environmental Management Strategies In Public Sector Organizations, Charles P. Roberts Mar 1999

Environmental Management Strategies In Public Sector Organizations, Charles P. Roberts

Theses and Dissertations

Environmental management research investigates environmental and ecological practices in organizations. Environmental strategy models or typologies are developed to classify organizations according to their environmental and ecological practices. Past research for environmental management strategy has focused on the profit sector versus the public sector. Drivers such as market and financial forces may not be as evident in the public sector as they are in the profit sector. This research explored environmental management strategies in public sector organizations. An environmental management strategy typology was developed to investigate the structural aspects of organizations. The typology and respective instruments were used in a case …

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Decision Analysis Methodology To Evaluate Organization, Shawn C. Thompson Mar 1999

Decision Analysis Methodology To Evaluate Organization, Shawn C. Thompson

Theses and Dissertations

The organizational structure of the civil engineer squadron's operations flight has undergone numerous changes over the last fifty years. Today the structure of the flight to the element level is mandated by Air Force Instructions; however, each unit is given the flexibility to organize below the element level. Most civil engineer units are struggling through the decision of how to organize their flights without a sound methodology to guide their efforts. Providing such a methodology is the objective of this thesis. To accomplish the objective, the history behind the operations flight structure was researched. In addition to this historical research, …

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Biodegradation Of Aircraft Deicing Fluid Components In Soil, Baron W. Burke Mar 1999

Biodegradation Of Aircraft Deicing Fluid Components In Soil, Baron W. Burke

Theses and Dissertations

Aircraft de-icing fluids (ADFs) are used worldwide to ensure safe aircraft operations. This research effort was conducted to analyze the biodegradation effects of two chemical components of ADFs, propylene glycol (PG) and tolyltriazole (TTA), in a high-clay soil. The research used four test methods; automated respirometry, high performance liquid chromatography (HPLC), microbial colony population counts (MCPC), and agar well diffusion tests (AWDT). The research was partitioned into two phases of investigation. Phase-one analyzed individual and combined ADF chemical components on uncontaminated soil. The presence of TTA, from 25 - 1,000 mg/kg, reduced the maximum respiration rate of 1,000 mg/kg PG …

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Modeling And Analysis Of Aerial Port Operations, Timothy W. Albrecht Mar 1999

Modeling And Analysis Of Aerial Port Operations, Timothy W. Albrecht

Theses and Dissertations

The focus of this thesis effort is gaining useful insight into aerial port operations by employing an animated simulation. Understanding airfield capacity, resources, and functioning allows greater accuracy and efficiency in both planning for future force structures and matching mobility assets with commanders' objectives. Two current simulations, ACE (Airfield Capacity Estimator) and BRACE (Base Resource Allocation and Capabilities Estimator), model mobility activities at the base level with some deficiencies. The model proposed by this thesis, APOM (Aerial Port Operations Model), will provide the mobility analyst an animated simulation with two, new measures of aerial port operations; a real-time estimate of …

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Dynamic Unmanned Aerial Vehicle (Uav) Routing With A Java-Encoded Reactive Tabu Search Metaheuristic, Kevin P. O'Rourke Mar 1999

Dynamic Unmanned Aerial Vehicle (Uav) Routing With A Java-Encoded Reactive Tabu Search Metaheuristic, Kevin P. O'Rourke

Theses and Dissertations

In this paper we consider the dynamic routing of unmanned aerial vehicles (UAVs) currently in operational use with the US Air Force. Dynamic vehicle routing problems (VRP) have always been challenging, and the airborne version of the VRP adds dimensions and difficulties not present in typical ground-based applications. Previous UAV routing work has focused on primarily on static, pre-planned situations; however, scheduling military operations, which are often ad-hoc, drives the need for a dynamic route solver that can respond to rapidly evolving problem constraints. With these considerations in mind, we examine the use of a Java-encoded metaheuristic to solve these …

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Cost-Benefit Analysis Of Cosolvent Flushing To Treat Groundwater Contamination Source Areas, Stacey L. Anason Mar 1999

Cost-Benefit Analysis Of Cosolvent Flushing To Treat Groundwater Contamination Source Areas, Stacey L. Anason

Theses and Dissertations

Dense non-aqueous phase liquids (DNAPLs) in the zone beneath the water table can be a virtually permanent source of groundwater contamination that cannot be remediated by currently available technologies. Cosolvent flushing is a new technology that has the potential to remediate these sites and could pose a solution to the problem of DNAPL source areas. A computer model was developed to determine the cost and time to remediate an aquifer using cosolvent flushing. Included in the model is a module to calculate the costs of recycling the alcohol that is used as the cosolvent. The model was validated using site …

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A Comparison Of Genetic Algorithm Parametrization On Synthetic Optimization Problems, Mehmet Eravsar Mar 1999

A Comparison Of Genetic Algorithm Parametrization On Synthetic Optimization Problems, Mehmet Eravsar

Theses and Dissertations

Meta-heuristics have been deployed to solve many hard combinatorial and optimization problems. Parameterization of meta-heuristics is an important challenging aspect of meta-heuristic use since many of the features of these algorithms cannot be explained theoretically. Experiences with Genetic Algorithms (GA) applied to Multidimensional Knapsack Problems (MKP) have shown that this class of algorithm is very sensitive to parameterization. Many studies use standard test problems, which provide a firm basis for study comparisons but ignore the effect of problem correlation structure. This thesis applies GA to MKP. A new random repair operator, which projects infeasible solutions into feasible region, is proposed. …

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Quality Function Deployment From An Operations Research Perspective, Eve M. Burke Mar 1999

Quality Function Deployment From An Operations Research Perspective, Eve M. Burke

Theses and Dissertations

The methodology of Quality Function Deployment (QFD) is compared to operations analysis standards. Of special concern is how Air Combat Command (ACC) uses QFD for the Modernization Planning Process (MPP). ACC digresses from the traditional use of QFD for incorporating quality into manufacturing processes to use it as a planning tool. ACC's goal in implementing QFD is to incorporate the demands of the Air Force mission into the modernization planning effort. ACC's use of QFD to identify and quantify current deficiencies and quantify the value of alternative future solutions has led to the investigation of inconsistencies with QFD, both generally …

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Using Simulation To Model The Army Recruiting Station With Multi-Quality Prospects, Edward L. Mclarney Mar 1999

Using Simulation To Model The Army Recruiting Station With Multi-Quality Prospects, Edward L. Mclarney

Theses and Dissertations

This thesis explores the application of simulation to the Army Recruiting Station. Included are the effects of leadership styles and policies, the effects of recruiters with different personality types, and differences in processing for varying types of recruits. Research included heavy emphasis into determining the effects of leadership on recruiter productivity. In addition, major changes were made to a previous simulation model. The changes allowed current research to be implemented into the simulation. This research is intended to help the United States Army Recruiting Command better understand how changes in the recruiting process and in leadership policies affect productivity.

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Pilot Inventory Complex Adaptive System (Picas): An Artificial Life Approach To Managing Pilot Retention, Martin P. Gaupp Mar 1999

Pilot Inventory Complex Adaptive System (Picas): An Artificial Life Approach To Managing Pilot Retention, Martin P. Gaupp

Theses and Dissertations

The retention of skilled pilots continues to be a problem that plagues the United States Air Force. After spending millions of dollars on training and education, it is disheartening to see the mass exodus of experienced aviators from the Air Force that has been occurring in the past decade. Many blame the economy, others the Air Force itself but few are able to accurately predict how or why they are all leaving. The current personnel models do not adequately determine retention rates. Complex adaptive systems theory, however, might provide some insight. By modeling the system at the pilot's level, allowing …

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Portfolio Selection Of Innovative Technologies Via Life Cycle Cost Modeling, Scott C. Naylor Mar 1999

Portfolio Selection Of Innovative Technologies Via Life Cycle Cost Modeling, Scott C. Naylor

Theses and Dissertations

High technology firms are faced with the dilemma of deciding which products to develop, which generations of technology to pass over, and which products to skip entirely. As competition among these firms increases and the life cycles of technological products shorten, there exists a great deal of pressure to bring products rapidly to the market. As a result, recouping the costs of research and development (R & D) and earning a profit becomes increasingly uncertain. Traditional life cycle cost models do not directly address shortened life cycles, time to market, or learning curve issues; all are critical factors in the …

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Expeditious Method For Estimating Cleanup Costs At Department Of Defense Installations In Korea, John M. Griffin Mar 1999

Expeditious Method For Estimating Cleanup Costs At Department Of Defense Installations In Korea, John M. Griffin

Theses and Dissertations

The purpose of this research was to develop and test a method that can be used to expeditiously estimate costs of hazardous waste site remediation at US DoD installations in Korea allowing decision-makers to formulate remediation strategy. This objective was addressed through answering the following questions: (1) What cost and time constraints do the decision-makers have in developing remediation cost estimates; (2) What degree of accuracy do the decision-makers require in cost estimates; (3) What estimating models are available for determining costs of remediation activities; (4) Have models been used to estimate remediation activities' costs at Korean installations; and (5) …

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Loop Gain Estimation For Adaptive Control, Jamey P. Sillence Mar 1999

Loop Gain Estimation For Adaptive Control, Jamey P. Sillence

Theses and Dissertations

The identification of a linear discrete-time control system's loop gain is addressed. The classical Kalman filter theory for state estimation in linear control systems is extended, and the control system's loop gain and state are jointly estimated. A rigorous analysis of the measurement situation under consideration yields explicit formulae for the loop gain's unbiased estimate and estimation error's covariance.

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Sorption Of The Aircraft Deicing Fluid Component Methyl-Benzotriazole In Soil, David L. Kellner Mar 1999

Sorption Of The Aircraft Deicing Fluid Component Methyl-Benzotriazole In Soil, David L. Kellner

Theses and Dissertations

The air transportation industry requires deicing/anti-icing (ADAF) fluids to maintain flight operations in cold weather conditions. Additives to the ADAF aid in the performance of these agents. Approximately 52M liters of concentrated aircraft deicing fluid are used in North America per year in an attempt to correct this safety problem. Among the additives to ADAF are corrosion inhibitors flame retardants, wetting agents, and thickening agents. Some of these agents are known to be toxic to microorganisms. Identification of the transport processes of these agents in the environment is a necessary first step to understanding how to remediate ADAF. Methyl-Benzotriazole (MeBT) …

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Analysis Of Radio Frequency Interference Effects On A Modern Coarse Acquisition Code Global Positioning System (Gps) Receiver, Kenneth D. Johnston Mar 1999

Analysis Of Radio Frequency Interference Effects On A Modern Coarse Acquisition Code Global Positioning System (Gps) Receiver, Kenneth D. Johnston

Theses and Dissertations

The purpose of this thesis was to investigate the performance of a twelve channel Standard Positioning Service (SPS) based (Global Positioning System (GPS) receiver using an eight state Kalman filter in a hostile radio frequency (RF) environment and to develop instructional tools for teaching RF interference on GPS receivers. The two types of jamming signals generated included Continuous Wave (CW) and Swept CW. Actual GPS and jamming signals were used in the research. The signals received from GPS satellites exhibit a Doppler shift which vary between approximately plus six Kilohertz. The Doppler shift frequency can be reasonably predicted for a …

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Unmanned Aerial Vehicle Mission Level Simulation, Jennifer G. Walston Mar 1999

Unmanned Aerial Vehicle Mission Level Simulation, Jennifer G. Walston

Theses and Dissertations

We develop an object-oriented simulation that models the surveillance and Active Suppression of Enemy Air Defense (SEAD) missions of the Unmanned Aerial Vehicle (UAV) RQ-1A Predator. The simulation, written in Java using the Silk simulation package, interfaces with a Reactive Tabu Search routing algorithm to provide optimal UAV routes. The routing algorithm is called by the simulation to account for changes in weather conditions and to provide a means of dynamically retasking the UAV. The simulation and analysis support a UAV Battlelab initiative to test the operational effects of proposed changes in Predator performance and UAV capability to perform in …

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A Validation Assessment Of Thunder 6.5'S Intelligence, Surveillance, And Reconnaissance Module, Francine N. Nelson Mar 1999

A Validation Assessment Of Thunder 6.5'S Intelligence, Surveillance, And Reconnaissance Module, Francine N. Nelson

Theses and Dissertations

A validation assessment of THUNDER 6.5's Intelligence, Surveillance, and Reconnaissance (ISR) module is accomplished using formulational and experimental validation techniques. A comparison of ISR purposes and processes according to military doctrine is made with the purposes and processes of ISR implemented within THUNDER 6.5. This comparison provides an overview of the process, an understanding of the level of aggregation within THUNDER, insight into possible problem areas in THUNDER, and a basis for improving THUNDER ISR processes. Sensitivity analysis of the ISR parameters as they relate to the Quality, Quantity, and Timeliness of ISR is also presented to provide insight into …

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Heat Transfer To The Inclined Trailing Wall Of An Open Cavity, Orval A. Powell Mar 1999

Heat Transfer To The Inclined Trailing Wall Of An Open Cavity, Orval A. Powell

Theses and Dissertations

Experimental and computational heat transfer investigations were performed on a cavity with an inclined trailing wall (20-degrees to the horizontal), simulating one under investigation for use in a scramjet engine. Heat transfer data are reported in the form of Stanton number obtained using a curve fit to the recorded transient surface temperature history under cold flow conditions. Ascending from the reattachment point, the Stanton number increased by nearly 50% due to flow compression. This effect of flow compression was also evident at the junction of the cavity floor and inclined trailing wall, where the Stanton number also increased by 50%. …

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Two-Stage Stochastic Linear Programming With Recourse: A Characterization Of Local Regions Using Response Surface Methodology, David T. Mills Mar 1999

Two-Stage Stochastic Linear Programming With Recourse: A Characterization Of Local Regions Using Response Surface Methodology, David T. Mills

Theses and Dissertations

The LP recourse problem applies to two-stage optimization problems where uncertainty in resource availability of the second stage hinders informed decision making. The recourse function affords a way to compensate "later" for an error in prediction "now." The literature provides a rich body of work on the optimization of such problems, but little research has been accomplished regarding the characterization of the surface in the local region of optimality, in particular sensitivity analysis. A decision maker faced with considerations other than the modeled objective function must be presented with a way to estimate the impact of operating at non-optimal decision …

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Solving The Multidimensional Multiple Knapsack Problem With Packing Constraints Using Tabu Search, Jonathan M. Romaine Mar 1999

Solving The Multidimensional Multiple Knapsack Problem With Packing Constraints Using Tabu Search, Jonathan M. Romaine

Theses and Dissertations

This paper presents a methodology for solving military aircraft load-scheduling problems modeled as a multidimensional multiple knapsack problem, Because of the computational time associated with applying conventional algorithms to this type of problem, we employ tabu search to determine how much cargo a heterogeneous group of aircraft can carry. This study extends the previous work of Chocolaad in two areas. First, we modify Chocolaad's algorithms to solve the multiple (rather than the single) knapsack problem under the constraints he defined for the Airlift Loading Problem. Second, we drop his assumption of a homogeneous group of aircraft. We validate our model …

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A Value Focused Approach To Determining The Top Ten Hazards In Army Aviation, Brian K. Sperling Mar 1999

A Value Focused Approach To Determining The Top Ten Hazards In Army Aviation, Brian K. Sperling

Theses and Dissertations

The United States Army Safety Center is challenged with identifying the top ten most severe hazards in Army Aviation. This research utilizes value-focused thinking and multiattribute preference theory concepts to produce a decision analysis model designed to aid decision-makers in their analysis process. The severity model is based on the Army's Risk Management doctrinal manual and has been tailored specifically for aviation related accidents and hazards. The model determines the severity and risk ranking for 65 categories of accidents and 24 existing hazards. A sensitivity analysis is conducted to examine the effects of variations in the weights of the top-level …

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A Comparative Analysis Of The Iridium® And Globalstar® Satellite Transmission Paths, Kenneth E. Crowe Mar 1999

A Comparative Analysis Of The Iridium® And Globalstar® Satellite Transmission Paths, Kenneth E. Crowe

Theses and Dissertations

Globalstar and Iridium will provide valuable global communications assets for business, humanitarian aid and military operations. However, the level of coverage and the quality of the transmission path of these systems are strongly dependent on the latitude of the user and, due to their orbital characteristics, both systems provide reduced levels of coverage at low latitudes. Additionally, the L- and S-Band frequencies utilized by these systems are prone to ionospheric interference at low latitudes. The results of extensive simulation analysis indicate that the Globalstar constellation architecture provides a considerably better transmission path than Iridium's in several important areas, including path …

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Technology Selection For The Air Force Research Laboratory Air Vehicles Directorate: An Analysis Using Value Focused Thinking, Michael F. Winthrop Mar 1999

Technology Selection For The Air Force Research Laboratory Air Vehicles Directorate: An Analysis Using Value Focused Thinking, Michael F. Winthrop

Theses and Dissertations

A technology selection model was developed for the Air Vehicles Directorate of Air Force Research Laboratory. The model was developed and demonstrated to aid in addressing the question of what technologies Air Vehicles' should invest in to remain consistent with Air Force values. Both Value-Focused Thinking and optimization approaches were used to identify the value of Air Vehicles technology, to provide insights to Air Vehicles' decision-makers, to determine where value gaps might exist with the scored alternatives, and to determine how sensitive the model was to changes. As a demonstration of the approach, seven technologies were scored, representing all three …

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Multi-Discipline Network Vulnerability Assessment, Karilynne Wallace Mar 1999

Multi-Discipline Network Vulnerability Assessment, Karilynne Wallace

Theses and Dissertations

Air Force Space Command has a mission to provide real-time, survivable, and enduring communications, surveillance, environmental monitoring, navigation, and warning....according to Air Force Space Handbook - A War Fighters Guide to Space. In order to prevent disruption of the critical networks in Space Command, a vulnerability assessment must be performed. The set of components called a vulnerability set, which could cause network disruption, must be identified and prioritized. In order to move beyond subjective prioritization, implementation of a quantitative methodology that measures the value of each vulnerability set is needed. This thesis proposes a technique for vulnerability assessment of a …

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Toward Development Of An Integrated Aerospace Power Doctrine, Toby G. Doran Mar 1999

Toward Development Of An Integrated Aerospace Power Doctrine, Toby G. Doran

Theses and Dissertations

This thesis discusses the state of the Air Force, decision making factors in the making of military doctrine, the definition of doctrine, Air Force doctrines today, new ways to develop doctrine, including models and hypothesis-research-analysis loops, space doctrine, control of space, space superiority and a call for aerospace power doctrine.

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Simsat: A Satellite System Simulator And Experimental Test Bed For Air Force Research, James E. Colebank, R. Dan Jones, Randall D. Pollak, Donald M. Mannebach, George R. Nagy Mar 1999

Simsat: A Satellite System Simulator And Experimental Test Bed For Air Force Research, James E. Colebank, R. Dan Jones, Randall D. Pollak, Donald M. Mannebach, George R. Nagy

Theses and Dissertations

SIMSAT (the SIMulation SATellite) is an AFIT-sponsored program to develop a laboratory-based physical satellite simulator. SIMSAT supports experimentation in areas of attitude control, precision pointing, and vibration suppression. SIMSAT development began with the purchase of a three-axis gas bearing which simulates a torque-free space environment. SIMSAT subsystems provide power, attitude control, telemetry, and structural support to experimental payloads. Project challenges included integration of attitude control software/hardware, high-output power storage devices, remote communications, high-frequency data collection, structural design, and computer display outputs.

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East Coast Abort Modeling With Rtls Elimination For The Space Shuttle-Liquid Fly Back Booster Launch System, Thomas L. Miller Jr. Mar 1999

East Coast Abort Modeling With Rtls Elimination For The Space Shuttle-Liquid Fly Back Booster Launch System, Thomas L. Miller Jr.

Theses and Dissertations

This study investigates the ability of the proposed Liquid Fly Back Booster, a replacement for the Space Shuttle's Solid Rocket Boosters (SRBs), to eliminate the need for the Return to Launch Site (RTLS) abort mode. A Fortran model of a nominal launch trajectory was perturbed to simulate a single Space Shuttle Main Engine-out (SSME-out) abort scenario at different times in the launch with the goal being to abort to the southern most landing site possible. The model accounts for vehicle lift, drag, dynamic pressure, throttling times and includes atmospheric effects to enhance fidelity. Results show the RTLS abort mode can …

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Progressive Failure Analysis Of Composite Panels, Stephen M. Spottswood Mar 1999

Progressive Failure Analysis Of Composite Panels, Stephen M. Spottswood

Theses and Dissertations

The objective of this research was to determine the physical response, including material failure, of a curved composite panel designed to resist transverse loading. The cause of the material failure, in the form of delamination, fiber and/or matrix failure, was determined through various criterion based on non-linear movement using a finite element analysis technique. Data generated both with and without the addition of progressive failure criteria, was compared with previously published experimental data, noting where the theory diverges from the experimental results. The inclusion of various failure criterion, to include maximum stress, Lee, and Hashin, provided a more realistic representation …

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Tip Vortex And Crenulation Effects In A Compressor Cascade With Moving Endwall, Barry W. St Germain Mar 1999

Tip Vortex And Crenulation Effects In A Compressor Cascade With Moving Endwall, Barry W. St Germain

Theses and Dissertations

The effects of changing Reynolds number and flow coefficients on the velocity and pressure flow fields within a linear cascade with moving endwall were investigated in this experimental thesis. All flow field measurements were taken at a constant compressor blade tip gap clearance of 1.0 % chord and endwall speed of 318.6 ft/s (97.1 m/s), with flow coefficients of 0.40, 0.52, 0.62 and 0.72. All data acquisition occurred in a plane 23 % chord downstream of the trailing edge plane of the linear cascade. Hotwire probes determined the complete passage, three-dimensional fowled behind both crenulated and regular blade geometries. Vector …

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Electrical Characterization Of Ion-Implanted 4h-Silicon Carbide, Christian P. Morath Mar 1999

Electrical Characterization Of Ion-Implanted 4h-Silicon Carbide, Christian P. Morath

Theses and Dissertations

Electrical characterization has been performed on ion-implanted p-type 4H-SiC to assess the activation efficiency and implantation-related damage recrystallization with the intention of developing an implantation/annealing scheme. Low doped (Na - Nd = 5x10(exp 15)/cu cm) epitaxial p-type layers grown by MOCVD were implanted with Al or B at doses ranging from 1x10(exp 13) to 1x10(exp 14)/sq cm at room temperature or 500 deg. C. The electrical technique of Temperature Dependent Hall Effect (TDHE) indicated that Al and B act as shallow acceptors 4H-SiC with ionization energies of ^252 and ^285 meV, respectively. The highest activation efficiency for Al and B …

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