Abstract: An accelerator for a projectile includes a coil; an H-bridge coupled to the coil with four relays S1-S4, and a controller to control current flow in the coil, wherein when relays S1 and S4 are on and relays S2 and S3 are off, current goes through the coil in one direction, and when the states of the relays are switched, current direction reverses, wherein switching the current direction ensures that the projectile has a positive acceleration.

Abstract: Epitaxial growth of a chirped superlattice with constant dopings is achieved with minimal growth interruption time. This is done by doping only one of the two compositions during growth of its layer. For example, in the growth of a plurality of alternating layers of InP and GaInAs to form the superlattice, either the InP layers are doped with an n-type dopant, such as silicon, or the GaInAs layers are doped with a p-type dopant, such as beryllium. Alternatively, InP can equally be doped p-type (with beryllium) and GaInAs can be doped n-type (with silicon). In either case, the doping scheme described herein is easily done during molecular beam epitaxial growth by opening and closing the shutter of the dopant (silicon or beryllium) source cell at the appropriate times. To the electrical carriers, the doping superlattice scheme of the present invention presents a uniform doping without any need to change the doping cell temperature.

Abstract: An epitaxial structure and method of manufacture for a field-effect transistor capable of high-speed low-noise microwave, submillimeterwave and millimeterwave applications. Preferably, the epitaxial structure includes a donor layer and/or buffer layer made from a semiconductor material having the formula AlP.sub.0.39+y Sb.sub.0.61-y.

Abstract: An epitaxial structure and method of manufacture for a field-effect transistor capable of low-noise and power applications. Preferably, the epitaxial structure includes an N-type barrier layer comprising a wide-gap semiconductor material having the formula Al.sub.1-y Ga.sub.y P.sub.0.71+z Sb.sub.0.29-z.

Abstract: An epitaxial structure and method of manufacture for a single heterojunction bipolar transistor capable of being utilized in high-speed and high-power applications. Preferably, the epitaxial structure comprises an N-type collector made from InP, a P-type base made from InP, and an N-type emitter made from a semiconductor material of approximately 39 mole percent AlP and approximately 61 mole percent Sb.

Abstract: An epitaxial structure and method of manufacture for a single heterojunction bipolar transistor capable of being utilized in high-speed and high-power applications. Preferably, the epitaxial structure comprises an N-type collector made from InP, a P-type base made from InP, and an N-type emitter made from a semiconductor material of approximately 39 mole percent AlP and approximately 61 mole percent Sb.

Abstract: A double heterojunction bipolar transistor (DHBT) is provided with a parabolic grade in bandgap at the base-collector junction. The parabolic grade in bandgap is close to parabolic in composition. The parabolic grade in bandgap is achieved by employing a chirped superlattice to mimic the parabolically varying alloy composition. Each period of the superlattice consists of one low-bandgap layer and one high-bandgap layer. The average composition in each period is determined by the relative thicknesses of these two layers. By varying the thickness ratio of these two layers approximately parabolically with (i) the distance from the base for a concave parabola and (ii) the distance from the collector for a convex parabola, the intended parabolic grade is achieved. The exact values may be computed numerically.

Abstract: High breakdown voltages for AlInAs layers in InP-based devices, such as a gate layer in an InP HEMT or a collector layer in a heterojunction bipolar transistor, are achieved by growing the AlInAs layer by MBE at a substrate temperature about 70.degree.-125.degree. C. below the temperature at which a 2.times.4 reflective high energy diffraction pattern is observed. This corresponds to a growth temperature range of about 415.degree.-470.degree. C. for a 540.degree. 2.times.4 reconstruction temperature. Preferred growth temperatures within these ranges are 80.degree. C. below the 2.times.4 reconstruction temperature, or about 460.degree. C. Higher breakdown voltages are obtained than when the AlInAs layer is grown at either higher or lower temperatures.

Abstract: An epitaxial structure and method of manufacture for a field-effect transistor capable of high-speed low-noise microwave, submillimeterwave and millimeterwave applications. Preferably, the epitaxial structure includes a donor layer and/or buffer layer made from a semiconductor material having the formula AlP.sub.0.39+y Sb.sub.0.61-y.