Abstract: A correction for NMR spin echo spectral data is obtained by adjusting the time origin of an extended density data set and transforming the adjusted origin data set of original density to the frequency domain.

Abstract: A power supply for helix and collector electrodes of a traveling wave tube is driven by an AC power source having a frequency of at least 500 KHz. The helix supply includes plural, stacked voltage doubler AC to DC modules responsive to the 500 KHz source. The collector supply includes plural AC to DC modules, each having a diode full wave rectifier bridge, connected in stacked relation. Each of the modules includes a transformer with a ferrite, toroidal core dimensioned so that it is not driven into saturation by the 500 KHz source. Each module also includes inexpensive, signal switching diodes having a recovery time of approximately 4 nanoseconds. The ratio of the collector to helix DC voltages is maintained constant by threading a common lead through the apertures of the toroidal cores of the helix and collector modules. A separate common lead threaded through the apertures of the toroidal cores in the collector modules is connected directly to the 500 KHz power source.

Abstract: In order to increase the efficiency of solar cells, a monolithic stacked device is constructed comprising a plurality of solar sub-cells adjusted for different bands of radiation. The interconnection between these sub-cells has been a significant technical problem. The invention provides an interconnection which is a thin layer of high ohmic conductance material formed between the sub-cells. Such a layer tends to form beads which serve as a shorting interconnect while passing a large fraction of the radiation to the lower sub-cells and permitting lattice-matching between the sub-cells to be preserved.

Abstract: The invention relates to a process for the low pressure chemical vapor deposition (LPCVD) of metal silicide, especially molybdenum silicide, on a substrate at a low temperature. The walls of a LPCVD reactor which contains a heated pedestal for holding a substrate are cooled and the pedestal is heated so the substrate temperature reaches a desired level, depending on the metal silicide to be deposited. A metal halide and a silane or disilane are fed separately into the deposition chamber and mixed behind a small baffle plate at the entrance. The metal silicide is deposited on the substrate surface. It is preferred that the substrate be pre-treated with H.sub.2 plasma before deposition.

Abstract: A valve for a wafer processing machine is formed with a wedge-shaped sliding gate. A folded wafer handling arm is stored within the wedge and pumped to keep the arm clean while the valve is closed.

Abstract: Synchronous apparatus capable of a variety of operational states responds to a sequence of digital control words, each specifying a desired state and persistence time of the state. The control words are furnished to the apparatus from a self-clocked FIFO in accord with the persistence code. A selected sub-sequence of digital control words in ROM is placed in an auxiliary FIFO upon detection of a corresponding token in the main sequence and control is passed to the auxiliary FIFO to furnish the sub-sequence to the apparatus. At the conclusion of the sub-sequence control is returned to the main FIFO and the main sequence is resumed.

Abstract: In a multi-cavity klystron amplifier tube, the gain-bandwidth product is improved and the amplitude response is made flatter by successive intermediate floating cavities downstream of the input cavity tuned to successively higher frequencies, and the drift lengths between them successively shorter.

Abstract: A probe having four spring-loaded tips contacts the backside of a semiconductor wafer in a processing machine. A current is induced across the outer tips and a voltage proportional to the sheet resistance of the wafer is measured across the inner tips. Wafer thickness is used to convert sheet resistance to bulk resistivity. Data on resistivity as a function of temperature is used to determine wafer temperature.

Abstract: Semiconductor wafers having patterns of steps and grooves defining microcircuit elements thereon are coated with metallic film by supporting the wafers individually adjacent a respective ring-shaped sputtering source in stationary relationship thereto. Within a short deposition time of approximately one minute, good uniformity of deposition across the main wafer plane is obtained by maintaining source-to-wafer spacing less than the diameter of the source, and an effective source diameter (D.sub.s) larger than the diameter of wafer (D.sub.w) with the coating being performed within an argon environment of 2 to 20 microns pressure. Good step coverage across all surfaces of steps and grooves is likewise obtained, and is further enhanced by confining the source-to-wafer spacing ranges to certain values within about 0.4 D.sub.s to 0.9 D.sub.s and the wafer diameter to certain values up to about 0.7 D.sub.s.

Abstract: An NMR instrument incorporating a cryogenic magnet includes a constant pressure device to maintain the pressure of cryogenic vapors at a constant value whereby a stable magnetic environment is maintained.

Abstract: In order to increase the efficiency of solar cells, a monolithic stacked device is constructed comprising a plurality of solar sub-cells adjusted for different bands of radiation. The interconnection between these sub-cells has been a significant technical problem. The invention provides an interconnection which is a thin layer of high ohmic conductance material formed between the sub-cells. Such a layer tends to form beads which serve as a shorting interconnect while passing a large fraction of the radiation to the lower sub-cells and permitting lattice-matching between the sub-cells to be preserved.

Abstract: The input signal to a TWT amplifier is predistorted in amplitude and phase to the inverse of the amplifier transfer characteristic by an adjustable circuit including a phase linearizing section and an amplitude linearizing section, both in series with the input signal and amplifier. Each section includes two pairs of back-to-front Schottky diodes. Preferably an additional diode is in series with one pair for the amplitude section. The diodes of each pair are of like polarity and opposite to the diodes of the other pair of the section. Additional diodes are connected between the pair junctions and ground, and adjustable D.C. bias fed into these junctions. Additional resistors and capacitors bridge the pairs, and are arranged into a phase delay network in one of the sections.

Abstract: A wide bandwidth linear motor system suitable for high performance applications such as driving the tuning plunger of a magnetron oscillator. The linear motor includes a coil assembly with a structure which suppresses secondary resonances, thereby permitting the linear motor to be used in a wide bandwidth servo control loop. The coil assembly includes a cylindrical coil support, a bushing coaxial with the coil support for attachment to the linear motor shaft, a plurality of radial ribs connecting the coil support to the bushing and a coil having multiple turns wound circumferentially around the coil support. The coil support is subdivided by axial gaps into at least two separate coil support elements, each connected by a radial rib to the bushing. Resonance of the coil support and the coil is suppressed by the separate coil support elements and the lossy connection therebetween.

Abstract: Apparatus for determining ion dose and ion dose uniformity of an ion beam scanned over a target plane in response to scanning signals includes a mask assembly for sensing the beam current at several different locations and providing a single beam current signal. The mask assembly includes a mask plate with sensing apertures and an annular Faraday cup aligned with the apertures for sensing beam current. The beam current signal is integrated over time to determine ion dose. A demultiplexer, in response to x and y scan signals, separates the beam current signal into separate signal components from each sensing aperture. Ion dose uniformity is determined by comparing the separate signal components, integrated over time, with an average value of the signal component.

Abstract: The tuned LC circuit of an NMR probe includes a coil center tapped to ground through a capacitance selected to constrain parasitic resonances to a frequency region below decoupler frequencies employed in the probe.

Abstract: A tactile pick includes a base and a lever attached beneath the base by a pivot. A load sensing device including a strain gauge is located between the base and the portion of the lever on one side of the pivot; the portion of the lever on the other side of the pivot is adapted to receive a semiconductor wafer. Rotation of the lever about the pivot induced by the weight of a wafer causes an actuator to depress a flexible member on which a strain gauge is mounted. The output signal of the strain gauge is processed by a controller to provide an output signal which varies monotonically with the magnitude of the weight placed on the wafer receiving portion of the lever. The pick is employed in connection with the wafer transport system which transfers wafers from a cassette to the pick lever.

Abstract: In a vacuum chamber wafer treating apparatus a wafer is heated or cooled by introducing a gas at a pressure of approximately 100 to 1000 microns in a region between the wafer and a heating element or heat sink. The gas conducts thermal energy between the wafer and heating element or heat sink.

Abstract: An NMR spinner having a separate drive pressure and radial bearing pressure includes a differential pressure actuated valve for bleeding a portion of the radial bearing gas to the drive jets to provide for a slow rotation.

Abstract: A wafer is introduced into a processing chamber on a transport device. Lifting pins receive the wafer from the transport device and lower the wafer to the surface of a chuck. Clamping pins lower and hold the wafer by means of enlargements on the ends of the clamping pins. Grooves on the surface of the chuck and internal channels in the chuck are used to supply gas to the back of the wafer for temperature control.

Abstract: A radiotherapy machine includes a microwave powered accelerator to produce an energetic beam of charged particles, bending and focussing magnets to parallel scan the beam in a plane and collimators to make the resulting parallel scanned beam into paraxial rays of charged particles or X-rays. The beam is intensity modulated as it is scanned to control dosage spatial distribution. The subject is moved perpendicular to the scanning plane in order to treat a 3-dimensional shape.