Ultralarge sale integrated circuit designs require multiple metal wiring layers for the formation of the device interconnections. Surface planarization and the deposition of high quality insulating films are critical fabrication steps related to the manufacture of these circuits. Planarization and dielectric deposition can be accomplished simultaneously using a spin-on process with hydrogen silsesquioxane (HSQ) resin to deposit amorphous SiO:H dielectric films. The use of this material in device manufacturing has increased as a result of the material's good planarization properties, eliminating the need for etchback procedures. More recently, it has been observed that HSQ-based films also provide the added benefit of relative permittivity less than SiO.,, which helps to minimize electrical delay. In order to obtain optimum properties from this material, tight process control and knowledge of the material's chemical behavior are necessary. Studies of the precursor material, film formation, and film properties have been performed. Also it is found that structural and compositional changes in the precursor during the film forming process play an important role in establishing the beneficial properties observed in HSQ-based dielectric films. InfroductionThe deposition of silicon dioxide thin films is a key step in the manufacture of semiconductor integrated circuits (ICs). Historically, ion beam sputtering and chemical vapor deposition have been used to deposit films in the 0.01 to 1.0 tim thickness range on dielectric, metal, and semiconductor surfaces. As circuit performance requirements have increased, the transistor density increased and the dimensions of the active device regions and circuit interconnections dropped well below 1.0 p.m. In these designs, multiple metal interconnection layers are essential. Today, IC designs with greater than three metal interconnection layers are common, and some microprocessors have as many as five levels. A common fabrication procedure for multilevel metal interconnection technology is the deposition of oxide films by spin coating silicon-based polymer solutions. The spin coating process planarizes the local wafer topography and facilitates the formation of void-free dielectric material between adjacent metal layers. Solutions of hydrogen silsesquioxane resin have emerged as a promising technology for the formation of planarizing oxide films. Oxide formation using this material has been shown to produce excellent local planarization and gap f ill1'2 and provides the added benefit of a dielectric constant lower than standard SiO,.Lower dielectric constant materials lower the capacitance between adjacent metal interconnections, in turn reducing electrical delay and paving the way to higher information processing rates.Hydrogen silsesquioxane (HSQ) resin is the polymeric analog of a family of spherosiloxanes previously explored by Five and Collins.5 These spherosiloxanes are highly ordered oligomers whose structure resembles a cage. The

We have developed conceptual designs of two petawatt-class pulsed-power accelerators: Z 300 and Z 800. The designs are based on an accelerator architecture that is founded on two concepts: single-stage electrical-pulse compression and impedance matching [Phys. Rev. ST Accel. Beams 10, 030401 (2007)]. The prime power source of each machine consists of 90 linear-transformer-driver (LTD) modules. Each module comprises LTD cavities connected electrically in series, each of which is powered by 5-GW LTD bricks connected electrically in parallel. (A brick comprises a single switch and two capacitors in series.) Six water-insulated radial-transmission-line impedance transformers transport the power generated by the modules to a six-level vacuum-insulator stack. The stack serves as the accelerator's water-vacuum interface. The stack is connected to six conical outer magnetically insulated vacuum transmission lines (MITLs), which are joined in parallel at a 10-cm radius by a triple-post-hole vacuum convolute. The convolute sums the electrical currents at the outputs of the six outer MITLs, and delivers the combined current to a single short inner MITL. The inner MITL transmits the combined current to the accelerator's physics-package load. Z 300 is 35 m in diameter and stores 48 MJ of electrical energy in its LTD capacitors. The accelerator generates 320 TW of electrical power at the output of the LTD system, and delivers 48 MA in 154 ns to a magnetized-liner inertial-fusion (MagLIF) target [Phys. Plasmas 17, 056303 (2010)]. The peak electrical power at the MagLIF target is 870 TW, which is the highest power throughout the accelerator. Power amplification is accomplished by the centrally located vacuum section, which serves as an intermediate inductive-energy-storage device. The principal goal of Z 300 is to achieve thermonuclear ignition; i.e., a fusion yield that exceeds the energy transmitted by the accelerator to the liner. 2D magnetohydrodynamic (MHD) simulations suggest Z 300 will deliver 4.3 MJ to the liner, and achieve a yield on the order of 18 MJ. Z 800 is 52 m in diameter and stores 130 MJ. This accelerator generates 890 TW at the output of its LTD system, and delivers 65 MA in 113 ns to a MagLIF target. The peak electrical power at the MagLIF liner is 2500 TW. The principal goal of Z 800 is to achieve high-yield Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

The electron beam produced by a compact plasma focus device has been investigated. The Mather geometry plasma focus electrodes were modified to permit extraction of accelerated electrons. Performance of the plasma focus as an electron accelerator using different gas species and pressures is investigated. Also, results from measurements of the beam parameters are given.

A unified theory of the electromagnetic wave propagation in a plasma column immersed in an axial magnetic field is developed, including the important influence of finite geometrical effects on wave dispersion properties. The analysis is carried out within the framework of a macroscopic cold fluid model. Coupled eigenvalue equations for the electromagnetic perturbations are obtained for an arbitrary density profile. For a flat-top density, a closed algebraic dispersion relation of the electromagnetic wave is obtained without any prior approximation. This transcendental dispersion relation is analytically solved in special cases of (a) uniform plasma, (b) infinite magnetic field, (c) zero magnetic field, (d) electrostatic perturbations, and (e) the low-frequency whistlerlike mode. In order to demonstrate the important influence of finite geometrical effects, the low-frequency whistlerlike mode is rigorously investigated for axisymmetric waves in a completely filled waveguide. From the analysis, it is shown that the whistlerlike mode propagates in the axial direction only when the total electron line density exceeds a critical line density. Moreover, the conventional dispersion relation of the low-frequency whistler mode is recovered only for a large plasma radius. Otherwise, the plasma geometrical effects play a pivotal role in wave propagation.

The resolution of Thomson spectrometers is examined. Charge, mass energy, and momentum resolutions are found as functions of collimation parameters and field strengths. The results are generally applicable to all Thomson spectrometer systems. In conjunction with this analysis, a compact Thomson spectrometer with high resolving power is described.