Abstract: An epitaxial layer of a quaternary III-V alloy of Ga, In, As, and P has its constituents proportioned for lattice matching to a substrate having a lattice constant falling within the range of 5.45 to 6.05 A. In addition, the constituents of the alloy are proportioned to provide a selected bandgap energy falling within the range of 2.23 to 0.35 electron volts; this corresponds to wavelengths of 0.55 to 3.5 microns. Near perfect lattice matched heterojunctions are provided between the epitaxial layer and the lattice matched substrate; these are useful for providing improved photocathodes and lasers, particularly in the infrared range of wavelengths between 0.8 and 2.0 microns.

Abstract: A lateral semiconductive device, such as a Gunn device or Impatt diode, is fabricated by depositing a barrier layer of beryllia over an epitaxial grown layer of N- type semiconductive material on an N+ type semiconductive wafer. The wafer is then thinned down, as by grinding and polishing. Electrode material is then deposited overlaying the N+ wafer layer for making ohmic contact thereto. The electrode material is etched to define at least a pair of laterally spaced electrodes, each making electrical connection to the epitaxial N- layer via the intervening layer of N+ wafer material. In the case of a Gunn device, the insulative barrier layer provides electrical insulation and prevents undesired leakage of current. In addition, it serves as a barrier to prevent metallic contact materials from diffusing into the epitaxial N- layer. Further, it serves as a heat sink between the active device and its mount.

Abstract: For supplying a bias (modulation) signal, either AC or DC, to a microwave circuit, a network consisting of a low pass filter is provided which presents a high isolating impedance to an extremely wide bandwidth of microwave frequencies, while allowing low frequency bias or modulating signals to be supplied to the microwave circuit without significant attenuation. The network consists of two helical inductors, one within the other, plus a bypass capacitor. The inner small inductor presents a high, non-resonant impedance to high microwave frequencies and the outer, larger inductor presents a high impedance to lower microwave frequencies. The bypass capacitor cooperates with the outer inductor to complete the filter circuit for the lower microwave frequencies. The smaller inductor's proximity to and within the larger inductor provides a distributed shunt capacitance to ground so as to terminate the filter for the higher microwave frequencies at the smaller inductor.

Abstract: An ultra wide band traveling wave tube amplifier is disclosed. The amplifier employs a helix derived slow wave circuit arranged for electromagnetic interaction with a beam of electrons passable axially through the helix circuit. Signals to be amplified within the passband of the circuit interact with the electron stream to produce an amplified output signal which is extracted from the helix and coupled to a suitable utilization device. The bandwidth of the traveling wave tube amplifier is substantially increased by the provision of a conductive circuit loading structure disposed surrounding the helix circuit and extending for at least half of its length and preferably for substantially its entire length.

Abstract: A very thin high quality active layer of a III-V material such as GaAs is formed on a temporary substrate on which an etch-resistant stopping layer of a material such as AlGaAs has been previously formed. Passivating layers are formed on the active layer, and the active layer is interfaced with a material which forms a permanent substrate. The temporary substrate is etched away with an etchant which is stopped by the stopping layer, following which the stopping layer is removed by etching with HF. The material in the active layer acts as a chemical stop for the HF, and consequently the etching process stops automaticaly at the boundary of the active layer, leaving that layer in the thin high-quality form in which it is grown. The etching rate of the stopping layer can be controlled by the proportion of Al in that layer.

Abstract: In a radio frequency transistor package, a layer of metallization is deposited on an electrically insulative thermally conductive ceramic substrate member serving as a heat sink. An insular region of the metallization serves as a pad for receiving a transistor die with the collector region of the transistor bonded to the insular region of metallization. The region of the metallization surrounding the pad comprises a ground plane. An apertured ceramic insulative spacer is bonded over the ground plane metallization with the aperture in registration over the transistor. Input, output and a pair of common lead metal strips are bonded to the upper surface of the spacer in generally coplanar configuration. The two common leads extend across the spacer adjacent opposite sides of the aperture in generally tangential relation thereto. The input and output leads are disposed in between the common leads and are interrupted by the central aperture in the spacer.

Abstract: A long wavelength photoemitter, for example a III-V semiconductor, having a work function reduction activation layer thereon, with means for overcoming the energy barrier between the semiconductor conduction band edge and the vacuum comprising means for thermally energizing the photoexcited electrons in the conduction band from a lower energy level therein to a higher "metastable" energy level in which they may reside for a sufficient time such that the electrons can pass with high probability from the elevated energy level into the vacuum over the energy barrier. In one embodiment, promotion of electrons to this higher energy level in the conduction band results from proper selection of the semiconductor alloy with conduction band levels favoring such room temperature thermal excitation.

Abstract: 2. In a reflex klystron tube apparatus, means for forming a beam of electrons, a resonator means positioned along the beam path, said resonator means being apertured for the passage of the beam of electrons therethrough for electromagnetic coupling to the beam, reflector means disposed on the side of the resonator remote from said means for forming the beam of electrons, said reflector means serving for reflecting the electrons incident upon the reflecting fields of said reflector means back through said resonator means substantially along the incident beam path, said means for reflecting the electrons formed and arranged to impart a slight transverse velocity to the electrons whereby they are caused to move transversely of and out of the beam in a small number of beam transits thereby minimizing unwanted amplitude and power modulation in the output signal of the tube apparatus.

Abstract: A traveling wave tube amplifier is disclosed. The amplifier employs a helix derived slow wave circuit arranged for electromagnetic interaction with a stream of electrons for amplifying wave energy applied to the slow wave circuit. A plurality of loading conductors are disposed about the outside surface of the slow wave circuit and extending lengthwise thereof. The conductors are arranged such that the spacing from the conductors to the slow wave circuit decreases toward its downstream end. The conductors are arranged such that they conduct radio frequency currents longitudinally of the slow wave circuit and do not appreciably conduct r.f. current in the direction circumferentially about the axis r.f. power flow on the slow wave circuit. Such loading conductors serve to decrease the phase velocity for wave energy on the circuit over the passband of the circuit. As a result, the interaction efficiency is substantially improved over the passband of the traveling wave tube amplifier.