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Polycrystalline diamond films produced by Microwave Plasma Enhanced Chemical Vapor Deposition were investigated for use as dielectric material for advanced passive devices needed in pulsed power applications. CVD diamond films that were heat treated in air from 250°C to 450°C for 2hrs. had very steady dielectric constants, ranging from 5 to 6.5, and very low losses, less than 0.005, over 100 to 106Hz at room temperature. Dielectric constants varied by less than 5% with temperature cycling to 500°C and losses remained very low (less than 0.01). Resistivities of CVD diamond heat treated in air were two to three orders of magnitude higher than the as-deposited samples. Breakdown strength, I-V and charge-discharge characteristics were also measured. Surface termination was examined to explain differences in the electrical performance of heat treated and as-deposited CVD diamond.

Thin barium titanate(BT), lead zirconate titanate(PZT), barium strontium titanate(BST) films are being developed for use in microelectronics, electromechanical and optoelectronic applications. Thin BaTiO3, Pb(ZrTi)O3 and (BaSr)TiO3 film capacitor devices were fabricated using RF sputtering techniques. The typical dielectric constant of these film capacitors was in the range of 300 to 1140. These film capacitors had dissipation factors between 0.2% to 0.6 % before annealing and 4-6% after annealing. The film capacitors have breakdown voltages in the range of 1×105 V/cm to 1.2×106 V/cm. The resistivity was in the range of 1010 to 1012 ohm-cm before annealing and 1013 to 1014 ohm-cm after annealing. The capacitance of films produced to-date had little dependence on frequency. Thermal cycling in the temperature range of 50 to 300°C had very limited impact on the capacitance and dissipation factor. Measurements of dielectric and material properties are reported.

Thin barium titanate (BT) film is being developed for use in microelectronics, electromechanical and optoelectronic applications. For this study rolled thin BaTiO3 film capacitors were fabricated using RF sputtering techniques. Capacitor grade aluminum foil was used as the bottom electrode. The top electrode was sputtered aluminum film, which was used for quick measurement purposes. The as-deposited ceramic film on aluminum foil was very flexible at room temperature and could be easily rolled. The foil was masked to preserve side electrodes. The typical dissipation factors (DF) of these BT film capacitors were in the range of 0.002 to 0.005. A low dissipation factor is extremely important for pulsed power or high power filtering applications. These BT film capacitors had a parallel resistance of 15 to 20 mega-ohm. With the thickness of the film being 8,000 Å, the average dielectric constant was calculated to be 25. The insulation resistance was about 138 giga-ohm.

This paper describes the potential of indirect liquid cooling to remove the waste heat generated while a MOS controlled thyristor (MCT) is operating at various power levels and switching frequencies. An MCT is mounted on a copper heat exchanger which is capable of removing up to 50 W of heat while maintaining the case temperature of the MCT below 50°C. At low switching frequencies, the MCT operates as expected at an applied voltage of 90 and 270 V. However, at 270 V, the device fails after a few minutes of continuous operation when the switching frequency is increased to 10 kHz.

An electrical system that will meet the requirements of a 1990s two-engine fighter is being developed in the Fault-Tolerant Electrical Power System (FTEPS) program, sponsored by the AFWAL Aero Propulsion Laboratory. FTEPS will demonstrate the generation and distribution of fault-tolerant, reliable, electrical power required for future aircraft. The system incorporates MIL-STD-1750A digital processors and MIL-STD-1553B data buses for control and communications. Electrical power is distributed through electrical load management centers (ELMC) by means of solid-state power controllers (SSPC) for fault protection and individual load control. The system will provide uninterruptible power to flight-critical loads such as the flight control and mission computers with sealed lead-acid batteries. Primary power is provided by four 60-kVA variable speed constant frequency (VSCF) generators. Buildup and testing of the FTEPS demonstrator is expected to be complete by Hay 1988.