Rf Sputtered Aluminum Oxide Films On Silicon

The physical and electrical properties of aluminum oxide films deposited on silicon by rf sputtering from an alumina target in an argon atmosphere were investigated as a function of sputtering power density in the range from 0.5 to 3 W/sq cm. The deposition rates ranged from 20 to 80 A/min. The density, index of refraction, and dielectric constant of the films increased while the etch rate decreased with increasing power density. The surface charge at the aluminum oxide-silicon interface was typically larger than 10 to the 12th. This charge increased with increasing sputtering power density and could be reduced to 7-8 x 10 to the 11th e/sq cm by annealing. The films exhibited trapping instabilities at room temperature but no polarization was observed under biastemperature stress. The characteristics of composite layers of thermally grown silicon dioxide and sputtered aluminum oxide layers on silicon were also investigated and found to exhibit low surface charge densities, no hysteresis, and a 'contact potential' as well as charge stored at the interface between the two insulators. (Author).

Results of a study on the deposition of thin-film dielectrics by RF sputtering are discussed. Source materials were silicon dioxide, aluminum oxide, tantalum oxide, and hafnium oxide, each of which was deposited onto metal electrodes and counterelectroded to complete the metal oxide metal capacitor structures for evaluation purposes. Depositions were conducted normally at 0.002 torr pressure utilizing a triode type sputtering system. Comparative rates of deposition of the dielectric materials ranged from 60 to 225 A/min for the maximum available power. The deposited films were amorphous in structure, although crystallites were dispersed in the hafnium oxide. Generally, the films displayed electrical and physical characteristics comparable to their counterparts formed by other processes, indicating that the sputtering process has the potential for translating the source materials to the substrates in a form suitable for thin-film dielectric applications. Yield study results are included in terms of non-shortened capacitors and their capability to withstand predetermined dielectric field strengths as a function of electrode areas ranging from 200 to 30,000 sq mil. (Author).

The results of a study on the deposition of thin-film silicon dioxide by RF sputtering are discussed. The dielectric source material was quartz which was sputtered and deposited onto aluminum electrodes and counterelectroded to complete the metal-oxide-metal capacitive structures. Depositions were conducted at pressures from 1-20 x 10 to the -3 power torr utilizing a triode type sputtering system wherein the processes of ionization of the gas and bombardment of the material are separated essentially. An electron beam is used to ionize the gas and produce the plasma. Application of an RF voltage (13.560 MHz) to a conducting plate placed behind the dielectric (quartz) plate translates the RF power by displacement current through the insulating source material. Interaction of RF voltage and plasma results in the establishment of a dc field between source and plasma which allows for the sputtering of the insulator. The capacitors were utilized to evaluate the dielectric, the device characteristics, and related process parameters. The effect of gas sputtering pressure, magnetic field strength, source-to-substrate distance, and power density on the rate of deposition is shown. Increased film thickness uniformity over a 3 in x 3 in area by optimum substrate positioning is indicated. Dielectric constant, dissipation factor, dielectric breakdown strength, insulation resistance, heat treatment, capacitance and dissipation factor over the range 400 Hz to 5 MHz, and effect of coating on thin-film resistive elements are reported. (Author).

The book addresses the problem of passivation at the surface of crystalline silicon solar cells. More specifically, it reports on a high-throughput, industrially compatible deposition method for Al2O3, enabling its application to commercial solar cells. One of the main focus is on the analysis of the physics of Al2O3 as a passivating dielectric for silicon surfaces. This is accomplished through a comprehensive study, which moves from the particular, the case of aluminium oxide on silicon, to the general, the physics of surface recombination, and is able to connect theory with practice, highlighting relevant commercial applications.

The world's experts on alumina are united in this effort to provide a comprehensive reference on the science and technology of alumina chemicals. Fifty-seven authors, representing 34 industrial firms, government agencies and universities, contributed to this book. This book covers the entire gamut of subjects relating to alumina from fundamental chemistry and material properties to applications and future uses. It includes a glossary and brief biographies of each author, detailing their experiences with alumina.

Backscattering Spectrometry reviews developments in backscattering spectrometry and covers topics ranging from instrumentation and experimental techniques to beam parameters and energy loss measurements. Backscattering spectrometry of thin films is also considered, and examples of backscattering analysis are given. This book is comprised of 10 chapters and begins with an introduction to backscattering spectrometry, what it can and what it cannot accomplish, and some ""rules of thumb"" for interpreting or reading spectra. The relative strengths and weaknesses of backscattering spectrometry in the framework of materials analysis are outlined. The following chapters focus on kinematics, scattering cross sections, energy loss, and energy straggling; backscattering analysis of thin films of various degrees of complications; the influence of beam parameters; and mass and depth resolutions and their relationships to the mass and energy of projectiles. Many examples of backscattering analysis are also presented to illustrate the capability and limitation of backscattering. Backscattering applications when combined with channeling effects are considered as well. The final chapter provides a list of references on the applications of backscattering spectrometry. This monograph will be a useful resource for physicists.