Materials Science and Engineering Commons^™

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 …