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Preapration Of Gallium Nitride Films By Medium Frequency Magnetron Sputtering

Posted on:2011-05-02Degree:DoctorType:Dissertation
Country:ChinaCandidate:M L YinFull Text:PDF
GTID:1100360305483477Subject:Particle Physics and Nuclear Physics
Abstract/Summary:PDF Full Text Request
InN, GaN and AlN are the most important semiconductor materials inⅢ-nitrides, their direct band gap is 0.7 eV,3.4 eV and 6.2 eV, respectively. Their ternary alloys are also direct band gap, which can be prepared to continued band gap (0.7eV-6.2eV) semiconductor materials. Their wavelength ranged from infrared to the ultraviolet, and covered the whole range of the visible light. The white light solid state display with the three primary colors of red, yellow and blue can be realized by the their ternary alloys. GaN and AlN can be prepared by metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), hydride vapor phase epitaxy (HVPE), pulsed laser deposition (PLD) and various evaporate and sputtering.α-Al2O3 and 6H-SiC are usually as the substrates for the growth of GaN and AlN films.The extensive application of GaN and AlN are restricted by the prices and the sizes of these substrates, which increasing the manufacturing cost of GaN and AlN materials and devices, however, the cost of grow GaN and the prepared of GaN-based optoelectronics and microelectronics devices can be greatly reduced by the growth of GaN on Si substrates, which are very important substrates for nitreides. Glass is the important substrate of solar cell, which is low cost and can be obtained with large aera. It has very important meaning if people can grow high quality GaN on glass, and the widely use of GaN is no longer a dream. The softening temperature of conventional glass adopted by the PV industry is in the range 500-600℃, however, the growth temperature of the traditional method for GaN growth is in the range 600-1000℃, so, it is need to find a growth technology with low-temperature. In the early 20th century, 90s, the reactive sputtering of metal Ga and the ion beam sputtering has been used to grow GaN film. The deposition temperature of the magnetron sputtering below the temperature of 600℃, and the magnetron sputtering is a method with low temperature, low cost and no pollution.In this thesis, GaN films were deposited on Si (111) and quartz glass by the self-designed MF twin targets magnetron sputtering system, and AlN films were deposited on Si (111) with the anode-layer ion source assistance. X-ray diffraction(XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), transmission electron spectroscopy (TEM),325nm He-Cd laser, Raman micro spectroscopy, etc, were used to measure the structure, optical and electrical properties of the films. The properties of the films were affected by the deposition pressure, bias, Ar/N2 ratio, target-substrate distance and the deposition time, and the growth and luminescence mechanism were investigated. The results obtained are as follows:1. GaN and AIN films were deposited at various conditions by the self-designed MF twin targets magnetron sputtering. A pair of sputtering targets was placed in the system, which connected to the two output electrode of the MF power. The two sputtering targets become cathodes alternately, which can significantly reduce or even prevent the generation of nitrides on the surface of the targets, at the same time, the reaction of the sputtering atom and the reactive gas increased, which lead to the significantly increasing of the deposition rate of the films, the highest deposition rate for GaN films reached 5.3μm/h.2. GaN films were deposited on Si (111) and quartz glass substrates by the self-designed MF twin targets magnetron sputtering, and AlN films were deposited on Si (111) substrates only. The effect of various deposition parameters (the deposition pressure, the bias, the N2/Ar ratio, the distance of target-substrate and the deposition time) on the GaN and AlN films were systematic studied. Both GaN and AlN films were polycrystalline, which were wurtzite structure and with the C-axis preferred orientation. GaN was columnar structure, which can be analyzed by the cross-section of GaN. The full width at half maximum (FWHM) of the best-quality GaN film is only-721 arcsec, and the FWHM of the best-quality AIN film is even only-612 arcsec.3. We added an anode-layer ion source to the MF twin targets magnetron sputtering system for the deposition of AIN films with good preferred orientation, smooth surface and dense structure. AIN films have clear advantages in terms of quality, dense, smoothness and deposition rate of AIN films deposited with anode-layer ion source assistance than AlN films deposited without anode-layer ion source assistance, the roughness of the smoothest AlN film deposited with anode-layer ion souce is only 0.13 nm.4. The optical absorption and photoluminescence spectrscaopy for GaN films were obtained, and the growth mechanism and the emission properties of GaN and AIN films grown at various deposition parameters were preliminary studies.
Keywords/Search Tags:GaN, AlN, Magnetron sputtering, Photoluminescence, Middle frequency, Nitride
PDF Full Text Request
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