Download or read book Growth and Characterization of Polycrystalline Silicon and Microcrystalline Silicon Carbide Thin Films Using ECR PECVD written by Bryan Kent Oliver and published by . This book was released on 1999 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: On the other hand, with He dilution at 15 mTorr the percent crystallinity obtained was also 86%, with decreasing crystallinity at lower pressures. We found that a dilution consisting of a 50%-50% mixture of H2-He, which allows a high ion bombardment deposition from the helium that is also benefited by the hydrogen etching effect, did not compromise the quality of the films. This plasma selection produced about 84% crystalline films, independent of the pressure setting. X-ray diffraction reveals the dominant crystal textures are 111 and 220 orientations, with 220 preferential growth at higher deposition pressures. The CH4/SiH4 flow ratio was found critical to the formation of microcrystalline SiC.
Download or read book The Growth of Microcrystalline Thin Films Using ECR PECVD written by Yung Moo Huh and published by . This book was released on 2002 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: A high rate growth method of hydrogenated microcrystalline silicon, [Mu]c-Si:H, and silicon-germanium, [Mu]c-(Si, Ge):H, has been developed with very low hydrogen dilution ratio on foreign substrates, using a remote electron cyclotron resonance - plasma enhanced chemical vapor deposition (ECR-PECVD) process. In this work, the key variable was the hydrogen dilution, ratio of hydrogen to silane, [H2]/[SiH4], which ranged from 3.3 to 10, adding helium systematically. Phase transition from amorphous to microcrystalline states was observed as the amount of added helium was varied. It has been found that hydrogenated microcrystalline silicon films with more than 70 % of crystalline volume fraction were formed at high growth rates of 3.2 Å/sec at low substrate temperature below 300°C from the mixture of silane and hydrogen with a low hydrogen dilution ratio of as low as 3.3. The addition of helium did not increase the growth rate significantly, but it quickly served as disrupting microcrystalline formation. In addition, the substrate temperature-dependent phase transition was observed. The structural, electrical and optical properties, by Raman shift, x-ray diffraction, dark and photo conductivity, activation energy of dark conductivity, and photosensitivity measurements, were investigated to grow good quality [Mu]c-Si:H films at the low hydrogen dilution ratio with high growth rates. The prominent peaks at 520 cm−1 from Raman Shift spectroscopy, crystalline peaks from x-ray diffraction pattern, small photosensitivity, and low activation energy of dark conductivity due to grain boundaries in microcrystalline silicon thin films indicated the characteristic of crystalline materials.
Download or read book Growth and Characterization of Microcrystalline Silicon Films and Devices Using Very High Frequency Plasma Enhanced Chemical Vapor Deposition written by Joshua Ali Graves and published by . This book was released on 2003 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is a report of the work done to grow hydrogenated microcrystalline Si materials and p-n junction photovoltaic devices using a 45MHz (VHF) PECVD process. Several parameters such as hydrogen dilution during growth, pressure, growth temperature, and ion bombardment were systematically varied during the growth process to study their effects on crystallinity and device properties. Crystallinity of the films was studied using Raman and x-ray diffraction techniques. It was found that the typical grain size was in the range of 10-25 nm, with larger grain sizes being obtained at higher deposition temperatures. It was also found that as the deposition pressure increased, the crystalline fraction decreased. This behavior is attributed to the decrease of ion bombardment at higher pressures. Optical measurements revealed the films to have absorption characteristics similar to those of c-Si. p+/n/n+ devices were fabricated on stainless steel and semi-transparent Mo/tin oxide substrates. Capacitance spectroscopy was used to estimate total defect and dopant densities in the base layer material. Good quality devices with fill factors approaching [difference]65% and open-circuit voltages of [difference]0.45 V could be fabricated using this technique. Diffusion length of holes in this material was estimated using quantum efficiency vs. voltage techniques, and it was found to be in the range of 1.2 micrometers.
Download or read book Amorphous Silicon Carbide Thin Films written by Mariana Amorim Fraga and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Silicon carbide (SiC) has been described as a suitable semiconductor material to use in MEMS and electronic devices for harsh environments. In recent years, many developments in SiC technology as bulk growth, materials processing, electronic devices and sensors have been shown. Moreover, some studies show the synthesis, characterisation and processing of crystalline SiC films. However, few works have investigated the potential of amorphous silicon carbide (a-SiC) thin films for sensors applications. This book presents fundamentals of amorphous silicon carbide thin films and their applications in piezoresistive sensors for high temperature applications.
Download or read book The Growth and Characterization of Beta Silicon Carbide Sic Thin Films by Chemical Vapor Deposition in a Low Pressure Vertical Reactor written by Kenneth George Irvine and published by . This book was released on 1992 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Growth and Characterization of Beta silicon Carbide Thin Films written by Bagher Bahavar and published by . This book was released on 1993 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanical Characterization of Polycrystalline 3C Silicon Carbide Thin Films written by Sharvani Nagappa and published by . This book was released on 2007 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Polycrystalline Silicon Thin Films by Metal induced Growth written by Elena A. Guliants and published by . This book was released on 2000 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Growth and Characterization of Micro crystalline Silicon germanium and Silicon carbon Films written by Karl Robert Erickson and published by . This book was released on 1998 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis reports on the growth chemistry and appropriate process parameters that result in the formation of micro-crystalline silicon-germanium and silicon-carbon films. The growth technique uses an electron-cyclotron-resonance-chemical-vapor-deposition apparatus. This apparatus allows the process engineer to control such parameters as the plasma resonance plane, substrate temperature, microwave power, vacuum pressure, gas flow ratios, and gas combinations. The plasma gas is hydrogen and the precursor gases are silane and germane. The hydrogen ions and electrons in the plasma dissociate the precursor gases into radicals that give rise to film growth on the substrate. The substrate temperatures are kept below 300 C so that deposition on polyimide substrates can be performed.
Download or read book Characterization of Polycrystalline Silicon Films Grown by LPCVD of Silane written by Justin Bradley Dorhout and published by . This book was released on 2006 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: Deposition of polycrystalline silicon by thermolysis of silane, SiH4, is a common technique for creating polysilicon films for a variety of applications. The deposition temperature and pressure greatly influence parameters relating to growth rate and film quality. These characteristics include film crystallinity and resulting grain orientation that determine the optical and electrical properties of the films and their suitability for particular applications. An empirical approach was taken to characterize the growth process and resulting film quality. Polycrystalline silicon films were grown to map a region of temperatures and pressures in the range of 575°C to 700°C and 200 mTorr to 500 mTorr. Deposition rate increased with increasing pressure, and was a strong function of temperature, increasing quickly then diminishing due to silane depletion. The crystallinity of films increased with temperature and decreased with pressure, exhibiting regions of rapid transition between amorphous and crystalline phases. X-ray diffraction was used to determine grain orientation and size. The 220 grains showed preferential growth while 111 and 311 grains were completely inhibited at low temperatures. Band gap energy decreased with increasing temperature and crystallinity. Resistivity of as-deposited, intrinsic films was very high. However, planar source phosphorus diffusion and annealing reduced resistivity to as low as 2.5·10−3 [Omega]·m.
Download or read book Mechanical Properties and Microstructural Characterization of Polycrystalline Silicon Thin Films written by Swaminathan Jayaraman and published by . This book was released on 1997 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Study of Polycrystalline Diamond Thin Films Grown in a Custom Built ECR PE CVD System written by Vidhya Sagar Jayaseelan and published by . This book was released on 2000 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: The increasing importance of high temperature electronics has necessitated a search for new materials. Silicon provides low reliability or fails to function altogether at elevated (>500F /260(C) temperatures. Diamond, being a wide-band-gap semiconductor, is a very promising candidate for these applications as well as others that function in adverse conditions. However, the present day diamond film technology, with respect to quality and consistency of properties of the films, has not seen the advancement required for its commercial application. This research is an effort to investigate the growth of diamond thin films to enable their application for advanced electronic devices. The first objective of the research was to construct a state of the art Electron Cyclotron Resonance Microwave Plasma Chemical Vapor Deposition (ECR-MPCVD) system for processing diamond and diamond like materials. Such a facility is the most advanced and powerful tool for CVD of poly-crystalline diamond and cubic Boron Nitride. Important factors like ease of operation and maintenance, stability and reproducibility of process conditions, reliability, safety, cost etc were considered while constructing the machine. The system was subjected to a series of tests to ensure that these factors were adequately satisfied. The second objective of this project was to grow polycrystalline diamond films under various conditions of chamber pressure, substrate temperature, hydrogen flow rate, composition and substrate pretreatment. The properties of the films grown under these conditions were evaluated by various modern characterization techniques such as optical microscopy, scanning electron microscopy, Raman spectroscopy and X-ray diffraction. Optical microscopy is an inexpensive, quick and effective method for initial evaluation of the uniformity and general morphology of the films obtained. Scanning electron microscopy gives information about the grain size, thickness, growth rate, uniformity, faceting, roughness, and continuous nature of the film. Raman spectroscopy is probably the most important characterization method for diamond films for electronic applications. It helps to identify the presence of diamond and the nature of the film. Raman spectrum is used to evaluate the quality of the diamond grains in the film, defect concentration and crystallinity. It also gives information about the presence of the non-diamond graphite phase and hence indirectly the intrinsic conductivity. XRD is also a positive identification tool. It was also used to derive information about the grain orientation with respect to the silicon substrate. The properties of the films obtained were correlated with the growth parameters and conclusions were drawn about the effect of these parameters on the film properties. This also helped in the characterization of the MPCVD reactor and in determining an effective range of parameters for future studies on the selective growth, long term growth, or growth of films with oxygen addition to the precursor.
Download or read book Characterization of Chemical Vapor Deposition Polycrystalline Silicon Thin Films written by Jean-Jacques Joseph Hajjar and published by . This book was released on 1985 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Growth and Characterization of Silicon Carbide Thin Films Using a Nontraditional Hollow Cathode Sputtering Technique written by James Huguenin-Love and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hydrogenated Microcrystalline Silicon Thin Film Growth in the DC Saddle Field PECVD System written by Erik Verne Johnson and published by . This book was released on 2006 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydrogenated amorphous silicon (a-Si:H) and microcrystalline silicon (muc-Si:H) thin films were grown at the threshold of the amorphous-to-microcrystalline phase transition in a modified direct current (DC) saddle field plasma enhanced chemical vapour deposition (SF-PECVD) system. For the first time, the microcrystalline content of the resulting films was successfully controlled through direct manipulation of the substrate surface bias during growth. This effect was quantified for multiple pressures. The as-grown microcrystalline content and the laser-induced crystallization of the films was quantified using Raman scattering spectroscopy. The optoelectronic and morphological properties of the films were measured. These measurements included UV-Vis and IR spectroscopy, temperature-dependent four-point conductivity, photoluminescence, atomic force microscopy, and spectroscopic ellipsometry. All measurements correlated well with the microcrystalline content of the films. The growth of muc-Si:H in an ion-bombarding environment was modeled using a general formalism applicable to all methods of muc-Si:H growth. The simulation results of the model showed good qualitative agreement to experimental findings from this work as well as the literature. The operation of the SF-PECVD system using a large-area externally applied substrate bias was examined under varying conditions and new limitations to the large area application of substrate bias were discovered. Three previously unidentified plasma operation regimes were identified that explain the role of substrate bias in controlling microcrystalline growth. A methodology for the design of SF-PECVD systems for the growth of muc-Si:H was described.
Download or read book Commencement written by Iowa State University and published by . This book was released on 1998 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Nucleation and Growth of Polycrystalline Silicon Carbide written by B.W. Sheldon and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
