Materials Science and Engineering Commons^™

In Situ Laser Etch-Depth Monitoring Of The Deep Reactive Ion Etching Process, Yuki Imura

Theses

A laser-based method for measuring feature thickness during the deep reactive ion etching process is investigated. Interference occurs between laser beam reflections from the mask surface, the mask/silicon interface, and the exposed silicon surface of a process wafer. Information from this interference signal allows the etch process to be characterized. Three methods are investigated: laser-on-SiO₂, laser-on-photoresist, and laser-on-both SiO₂ and silicon at a mask edge.

The measured data from these experiments are found to be in good agreement with theoretical calculations. Differences in reflected beam amplitude and interference fringe frequency represent well the differences SiO₂ and …

Characterization And Corrosion Of Bcc-Tantalum Coating Deposited On Aluminum And Steel Substrate By Dc Magnetron Sputtering, Chirag Joshi

Theses

Tantalum is one of the most versatile highly refractory corrosion-resistant metals. Tantalum coating can be used as an effective corrosion barrier if it is continuous, free from defects and it adheres well to the substrate. A DC magnetron sputtering technique was used to deposit tantalum on aluminum and steel. X-ray diffraction measurements revealed that the tantalum films produced by sputtering had two crystallographic structures: a body centered cubic α-phase and a metastable tetragonal β-phase. Tough and ductile alpha phase tantalum is preferred over the hard and brittle beta phase tantalum, as a protective coating. Alpha phase coatings were successfully deposited …

Electrical Properties Of Ultra Thin Al2o3 And Hfo2 Films As Gate Dielectrics In Mos Technology, Vishal R. Mehta

Theses

The rapidly evolving silicon industry demands devices with high-speed and low power consumption. This has led to aggressive scaling of the dimensions in metal oxide semiconductor field effect transistors (MOSFETs). The channel length has been reduced as a result of this scaling. The industry favorite, SlO₂, has reached limitations in the thickness regime of 1-1.5 nm as a gate dielectric. High-_κ gate dielectrics such as Al₂0₃ and HfO₂ and their silicates are some of the materials that may, probably, replace SlO₂, as gate dielectric in the next four to five years. …

Formation And Characterization Of N/P Shallow Junctions In Sub-Micron Mosfets, Sridhar Madishetty

Theses

Semiconductors are the burgeoning industries in today's information age. Silicon based microelectronic devices are shrinking day-by-day in accord with the scaling dimensions reported by the International Technology Roadmap for Semiconductors (ITRS). There have been many semiconductor models and simulation programs constantly keeping pace with the continuously evolving scaling dimensions, process technology, performance and cost. Electrical characterization plays a vital role in determining the electrical properties of materials and device structures. Silicon based Metal Oxide Semiconductor Field Effect Transistor (MOSFET) forms the basis of Complimentary Metal Oxide Semiconductor (CMOS) circuits. Today's aggressive scaling approaches in silicon Integrated Circuit (IC) technology require …

Crystallographic Structure And Mechanical Properties Of Tantalum Coatings On Steel Deposited By Dc Magnetron Sputtering, Charanjeet Singh Paur

Theses

Tantalum metal exhibits excellent erosion and corrosion resistance property. Hence, tantalum coatings are investigated for protection of steel surface exposed to mechanical stresses, high temperature, and corrosive environment. Such conditions exist inside large army gun barrels. The goal of this work was to contribute to the development of technology for tantalum coating of steel, which would replace the presently used electrochemical chromium deposition. A DC magnetron sputtering process was used to deposit tantalum coatings on steel substrates. In sputtering, tantalum is deposited in two phases: ductile, body-centered cubic (bcc) phase (a-phase) and a metastable, brittle tetragonal ß-phase. Only a-phase of …

Formation & Characterization Of P/N Shallow Junctions In Sub-Micron Mosfets, Samrat G. Chawda

Theses

The formation of shallow junctions in the source and drain regions is a major challenge to the continued success of scaling of complementary metal oxide semiconductors (CMOS) circuits. The formation of these device structures requires low-energy ion implantation and rapid thermal annealing (RTA). One of the processes which has been shown to be advantageous is spike annealing, with fast ramping and short dwell time at maximum temperature. This work is a study of the effects of implant energy, implant dose and annealing cycles on the reverse-bias leakage current in the diode junction. The reversebias leakage is the study of junction …

Development Of An Integrated Photonic Sensor For Monitoring Hazardous Organics, Dianhong Luo

Dissertations

In this study, an integrated photonic sensor has been designed and fabricated for the purpose of monitoring hazardous organics in the environment. The operation of the sensor is based on the principles of the Mach-Zehnder interferometry. The sensor consists of a patterned waveguide structure made of phosphosilicate core and silica cladding. LPCVD processes were developed to produce undoped cladding and doped core silicon dioxide films. Diethylsilane (DES), Trimethylphosphite (TMP) and oxygen were used as the precursors for the deposition process. The effects of the O₂/DES ratio and deposition temperature on the properties Of SiO₂ films were investigated. …

High Solid Loading Aqueous Base Metal/Ceramic Feedstock For Injection Molding, Mohammad Behi

Dissertations

Increasing volume fraction of metal powder in feedstock provided lower shrinkage. Reduction of the shrinkage results in better dimensional precision. The rheology of the feedstock material plays an important role to allowing larger volume fractions of the metal powder to be incorporated in the feedstock forinulations. The viscosity of the feedstock inainly depends on the binder viscosity, powder volume fraction and characteristics of metal powder.

Aqueous polysaccharide agar was used as a baseline binder system for this study.The effect of several gel-strengthening additives on 1.5wt% and 2wt% agar gel was evaluated. A new gel-strengthening additive was found to be the …

Characterization Of Alpha And Beta Phases Of Tantalum Coatings, Anto Yohannan

Theses

Sputtered tantalum forms two phases - α and β. The α and β phases have distinctly different crystalline structures and properties. The structure and the causes of formation of the β phase are still being studied by researchers. This is a study to distinguish and characterize these two phases. Samples from Bennet Labs and NJIT were characterized using techniques such as SEM, EDX, XRF, XRD, TEM and XAFS. Samples deposited at NJIT were used for an experimental study on the conditions favoring the formation of the phases, by depositing tantalum on heated steel and silicon substrates, additionally TEM analysis was …

Low Energy Implantation Of Boron With Decaborane Ions, Maria Angela Albano

Dissertations

The goal of this dissertation was to determine the feasibility of a novel approach to forming ultra shallow p-type junctions (tens of nm.) needed for future generations of Si MOS devices. In the new approach, B dopant atoms are implanted by cluster ions obtained by ionization of decaborane (B₁₀H₁₄)vapor. Each B atom carries only ~9% of the cluster kinetic energy and the B dose per unit charge is 10 times larger than in the case of monomer ion beams. Thus, the problems of spacecharge, limiting the extraction and transport of low energy (< = 1 keV) beams of B⁺ ions, can …

Deposition Of Tantalum On Steel By Sputtering, Bhavin Shah

Theses

Recent interest in tantalum deposition comes from two different applications. One is in microelectronics where thin tantalum films (< 1 µm) are used as diffusion barrier layers for copper interconnects. The other involves its application as a material for corrosion and wear resistant coating on surfaces that are subjected to high stresses and harsh chemical and erosive environments.

This thesis is a part of the investigation done at the Ion Beam and Thin Film Research Laboratory at NJIT to study the deposition conditions and properties of tantalum thin films. It includes the design and construction of Planar D.C. Magnetron Sputtering System and Cylindrical D.C. Magnetron Sputtering System for deposition on the planar and cylindrical surfaces of steel, respectively. The electrical characteristics of the cylindrical system were tested in a range of pressures and conditions for initiation and maintaining of …

Preparation And Properties Of Tantalum Silicide Films On Silicon Substrates, Lei Jin

Theses

Tantalum silicide (TaSi₂) thin films were sputter deposited on p- type and n- type silicon substrates using VARIAN 3125 magnetron DC sputtering system with TaSi₂ target. The thicknesses of TaSi₂ thin films considered in this study are 200Å, 600Å and 1000Å, respectively. The TaSi₂/Si wafers were annealed at temperatures in the range of 400 to 900°T. The sheet resistances of TaSi₂ thin films with various thicknesses were measured by four-point probe before and after annealing. The sheet resistance decreases with increase in annealing temperature and decreases with the increase in thickness of TaSi …

Nanoporous Sio2/Vycor Membranes For Air Separation, Mihir Tungare

Theses

Porous Vycor tubes with 40Å initial pore diameter were modified using low pressure chemical vapor deposition (LPCVD) of silicon dioxide N0₂). Diethylsilane (DES) in conjunction with nitrous oxide (N₂O) was used as a precursor to synthesize these SiO₂ films. The aim of this study was to obtain a considerable selectivity between species of comparable size and hence N₂O was used. The use of N₂O was believed to make the process self-limiting. DES was allowed to flow through the tube and N₂O on the outside in the chamber at 550°C …

Synthesis And Characterization Of Low Pressure Chemically Vapor Deposited Boron Nitride And Titanium Nitride Films, Narahari Ramanuja

Dissertations

This study has investigated the interrelationships governing the growth kinetics, resulting compositions, and properties of boron nitride (B-C-N-H) and titanium nitride (Ti-N-Cl) films synthesized by low pressure chemical vapor deposition (LPCVD) using ammonia (NH₃)/triethylamine-borane and NH₃/titanium tetrachloride as reactants, respectively.Several analytical methods such as the FTIR, UVNisible spectroscopy, XPS, AES, RBS, SEM, and XRD were used to study the stoichiometry and structure of the deposited films.

The B-N-C-H films were synthesized over a temperature range of 300 to 8500C at various flow rate ratios of the reactants and total pressure range of 50 to 150 mTorr. …

Characterization Of Tantalum Coatings On Steel Substrates, Prabha Shivaramkrishnan

Theses

Sputtered tantalum can be used as an effective corrosion resistant barrier if the coating is continuous, free from defects and is adherent to the substrate it is intended to protect. For corrosion-applications 100% bcc phase tantalum is preferred. X-ray diffraction results indicate that sputtered tantalum deposits typically contain a mixture of bcc and beta phases. Depending on the deposition conditions the morphology of tantalum coatings as studied using scanning electron microscopes can vary from irregular, dendritic structure to a defined step type structure. A "cauliflower type" structure has also been observed. Extended x-ray absorption fine structure measurement was used to …

Synthesis And Characterization Of Silicon Dioxide Films Using Diethyl Silane And Oxygen, Kiran Kumar

Theses

This study focuses on producing thin and thick silicon dioxide films towards the fabrication of integrated optical sensor capable of monitoring and determining in-situ, the concentration of numerous analyze species simultaneously. In this study, diethylsilane (DES) has been used as a precursor to produce silicon dioxide films by low pressure chemical vapor deposition. The films were synthesized with two different flow ratios of oxygen to DES in the temperature range of 550°C to 800°C at a constant pressure of 200mTorr. The films deposited with lower oxygen to DES flow ratio have very high growth rate but suffer from high tensile …

Plasma Enhanced Chemical Vapor Deposition Of Diamondlike Carbon Films Using Acetylene, Sriram Vishwanathan

Theses

This study is focussed on the synthesis and characterization of diamondlike carbon (DLQ films deposited on silicon wafers and glass by plasma enhanced chemical vapor deposition (PECVD), using acetylene (C₂H₄) as a precursor. The process parameters, such as temperature, pressure, power and reactant gas flow rate have been systematically varied and their effects on the film growth rate and properties were investigated. The optimized deposition condition appeared to be at 150°C, 200mTorr, 200 Watts and flow rate = 25 sccm. For these conditions, the films were hard and found to have good adhesion to the substrate, …

The In0.75ga0.25as/In0.52al0.48as/Inp Hall Effect Magnetic Field Sensor, Oleg Mitrofanov

Theses

The magnetic field sensor is produced from III-V group semiconductor materials. The structure is designed for molecular beam epitaxy growth technique (MBE) on the semiinsulating InP substrate. The sensitive element is the In_0.75Ga_0.25As/In_0.52Al_0.48As heterostructure. The sensor uses the classic Hall effect in two-dimension electron gas (2DEG) formed at pseudomorphic strained epilayer of In_0.75Ga_0.25As. Properties of the 2DEG are preferential for the Hall effect sensor performance. Comparatively to bulk, electron mobility is higher. The device combines high magnetic field sensitivity and temperature stability. The sensor is designed for operation …

Low Pressure Chemical Vapor Deposition Of Boron Nitride Thin Films From Triethylamine Borane Complex And Ammonia, Narahari Ramanuja

Theses

Boron nitride thin films were synthesized on Silicon and quartz substrates by low pressure chemical vapor deposition using triethylamine-borane complex and ammonia as precursors. The films were processed at 550°C, 575°C and 600°C at a constant pressure of 0.05 Torr at different precursor flow rates and flow ratios.

Several analytical methods such as Fourier transform infrared spectroscopy, x- ray photo-electron spectroscopy, ultra-violet/visible spectrophotornetry, ellipsometry, surface profilometry and scanning electron microscopy were used to study the deposited films. The films deposited were uniform, amorphous and the composition of the films varied with deposition temperature and precursor flow ratios. The stresses in …

Melt Hydroperoxidation Polypropylene With Potential Application In Pollution Control, Zeena Cherian

Theses

The primary objective of this study is to introduce tertiary hydroperoxide functional groups into polypropylene (PP) melt by injecting air. This was done first by mixing additive free polypropylene powder with air in a batch mixer. The influence of air flow rate, temperature, mixing time and rotor RPM on the concentration of hydroperoxide groups were studied. Iodometric analysis and fourier transform infrared spectroscopic analysis were the techniques used to detect and quantify the concentration of hydroperoxide groups. In the second phase of the study, hydroperoxide groups were introduced in polypropylene through reactive processing in a single screw extruder. It was …

Synthesis And Characterization Of Phosphosilicate Glass Films By Lpcvd For Sensor Application, Hui Wu

Theses

This study was dedicated to the synthesis of the thin film materials required to fabricate the waveguide and the reference arm barrier for integrated optical sensor. Phosphosilicate glass (PSG) thin films were synthesized on silicon and quartz wafers by LPCVD using Ditertiarybutylsilane(DTBS), Trimethylphosphite(TMP) and oxygen as precursors. The films were processed at different temperatures between 600°C and 700°C at a constant pressure, and at different flow rate of TMP.

The effect of TMP flow rate and deposition temperature on deposition parameters and the properties of PSG films were investigated. The films deposited were uniform, amorphous, low stress and the composition …

Synthesis And Characterization Of Hafnium Carbide Thin Films, Wiriya Thongruang

Theses

Hafnium carbide thin films of various characteristics were deposited on silicon substrates using dc magnetron sputtering. A HfC target was used as a sputtering source and Ar was used as a sputtering gas during deposition. The variables investigated were total sputtering gas pressure and power. Optimum characteristics were achieved with a total sputtering gas pressure of 5 mTorr and power of 200 W. No evidence for oxidation of the film was found at a depth below 400A for deposited and annealed films. Binding characteristics were obtained from ESCA data. The compressive film stress increased when sputtering gas pressure decreased. The …

Relaxation And The Nature Of Electrical Stress Related Defects In Ultra-Thin Dioxide On Silicon, Lihui Xie

Theses

The instability of defects created in ultra-thin insulator, metal-oxide-silicon devices biased in the direct tunnel regime is investigated. For the case of electron injection from the silicon substrate, nearly complete defect relaxation is observed after the bias is removed, allowing the possibility of re-generating the defects. Modeling the defect generation process and examining differences between initial and subsequent degradation periods lead to an improved picture of both the relaxation process and the nature of the involved defects.

Low Pressure Chemical Vapor Deposition Of Silicon Nitride Films From Tridimethylaminosilane, Xin Lin

Theses

In this study amorphous stoichiometric silicon nitride films were synthesized by low pressure chemical vapor deposition (LPCVD) using tri(dimethylamino) silane (TDMAS) and ammonia (NH₃). The growth kinetics were determined as a function of temperature in the range of 650 - 900 °C, total pressure in the range of 0.15 - 0.60 Torr, and NH₃/TDMAS flow ratio in the range of 0 - 10. At constant condition of pressure (0.5 Torr), TDMSA flow rate (10 sccm) and NH₃ flow rate (100 sccm), the deposition rate of as-deposited silicon nitride films was found to follow an Arrehnius …

Low Pressure Chemical Vapor Deposition Of Silicon Nitride Films From Ditertiarybutylsilane, Xiangqun Fan

Theses

In this study amorphous stoichiometric silicon nitride films were synthesized by low pressure chemical vapor deposition (LPCVD) using DTBS (ditertiarybutylsilane) and ammonia (NH₃). The growth kinetics were determined as a function of temperature in the range of 600-900 00, pressure in the range of 0.2-1.1 Torr, DTBS flow rate in the range of 10-50 sccm, and NH₃/DTBS flow ratio in the range of 5-20. At constant condition of pressure (0.5 Torr), DTBS flow rate (10sccm) and NH₃ flow rate (100 sccm), the deposition rate of as-deposited silicon nitride films was found to follow an Arrehnius …

Processing, Structural And Electrical Properties Of Sic, Mark Farhad-Garousi

Theses

Cubic silicon carbide films grown by chemical vapor deposition (CVD) on silicon substrates typically have n-type conductivity at 300 °K dominated by a heavily compensated donor with a binding energy in the < 20 meV range. Binding energies <20 meV are not expected in SiC for isolated donors because the shallowest expected binding energy for an electron bound to an isolated donor is approximately 47 meV. The work done on this topic by a few group of scientists has been studied.

Laser Treatment Of Ceramic Coatings On Defective Ceramic Glazed Tile, Gousinn Yu

Theses

Laser surface melting treatment was achieved by a 2 Kw CO2 surgical laser system.The partially defocused laser beam provided a circular spot with an annular energy distribution on the sample.

It is certain that laser surface treatment will do the job of repairing in defective ceramic tiles. All glazes provided by American Standard were tested for an ability of withstand laser treatment when coated on to a glazed tile. In order to repair the defective ceramic tile it is necessary to patch the damaged region with a cement. The cement must then be glazed in order to match that of …

Laser Ablation Of Silicon Surfaces : The Effects Of A Low Level Background Light, Taposh Kumar Gayen

Theses

The performance of high speed optoelectronic and microelectronic devices largely depends on the uniqueness and development of the fabrication technology. Laser ablation has proven to be an effective three dimensional surface patterning technology. In this thesis, we present findings on the patterning of semiconductor surfaces using laser ablation in air as well as in solutions.

In this thesis, we suggest that the depth of a pattern induced on silicon by firing a pulsed excimer laser in air varies almost linearly with the number of pulses. We report that a He-Ne laser as a background light source has virtually little or …

Synthesis And Characterization Of Silicon Nitride Films Deposited By Plasma Enhanced Chemical Vapor Deposition Using Diethylsilane, Yanyao Yu

Theses

Silicon nitride thin films were deposited on silicon substrates using Diethylsilane (DES) and ammonia by Plasma Enhanced Chemical Vapor Deposition (PECVD) over a temperature range of 100 - 300°C, a pressure range of 0.2 - 0.6 torr, and a ratio of NH₃/DES was varied from 6 - 26. The R.F. power and frequency were kept at 0.15 watts/cm^{2 and 100 KHz respectively. DES flow rate was set at 15 sccm for all experiments in this study. One set of experiments were performed at different values of one parameter while the other parameters were kept constant.}

The deposition …

Synthesis And Characterization Of Lpcvd Boron Nitride Films For X-Ray Lithography, Wen-Pin Kuo

Theses

Boron nitride thin films were deposited on silicon and fused quartz substrates using ammonia and the liquid precursor borane-triethylamine complex (TEAB) by low pressure chemical vapor deposition over a temperature range of 300-850°C, a pressure range of 0.21-0.6 torr, and an ammonia flow rate range of 0-740 sccm. An increased in the nitrogen content in the film due to the addition of ammonia flow resulted in a pronounced improvement in the optical transmission, an increase in the film uniformity and a decrease in the depletion effect. IR spectra of the films showed an asymmetrical wide band centered around 1400 cm …