Materials Science and Engineering Commons^™

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, …

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 …

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 …