Abstract: Refractory metals or ceramics are diffusion bonded or densified by assembling the workpieces to be bonded, wrapping the assembly with carbon yarn, heating the wrapped assembly, cooling the assembly and unwrapping. The expansion of the workpieces together with the shrinking of the carbon yarn produces tremendous pressures which cause bonding and densifying of the workpiece.

Abstract: A light source with appropriate optics focusses light on the wafer surface during deposition, while a nearby collector is biased to collect photoemitted electrons from the growing surface. A pico ammeter can be used to convert the small oscillatory current detected to a substantial voltage signal which can be recorded or processed by computer or other sutiable device. The light must contain wavelengths at energies close to or greater than the energy of the photoemission threshold. The detected photoemitted electron signal has an oscillatory component occurring due to the growth of epitaxial layers. This oscillation has frequency 1/.tau., where .tau. is the monolayer accumulation time.

Abstract: A method of mapping implanted ion dose uniformity is disclosed in which wafers of polysilicon-on-silicon or polysilicon-on-oxidized-silicon are implanted with the ion dose to be mapped and then scanned in a spectrophotmeter using monochromatic radiation. An interference spectral technique is used to achieve improved sensitivity while preserving thermal and electrical properties close to those of actual devices.

Abstract: In a chemical vapor deposition apparatus for coating semiconductor wafers, the wafer is held face down in the reaction chamber. A radiant heat source above the wafer and outside the reaction chamber. The wafer is held on a ring chuck by means of a retractable clamp heats the wafer from its backside to a temperature in excess of 1000.degree. C. rapidly. The radiant heat source includes cylindrical lamps placed in a radial pattern to improve heating uniformity. In the selective tungsten process the temperature of the wafer is raised from ambient to about 600.degree. C. while flowing process gases. At the upper temperature range the heating source can be rapidly cycled on and off to improve the uniformity of coating.

Abstract: An assembly is provided for supporting semiconductor wafers individually within a support while permitting processing of both faces of a wafer as well as facilitating rapid insertion and removal of wafers into the support. Each assembly includes a wire clip having an arcuate tip used to grasp the wafer. The wire clip can be moved in two planes by actuating mechanisms, thereby moving the clip out of the plane of wafer processing and facilitating loading in the wafer processing plane.

Abstract: An ion source for an intense ion beam from a solid source is formed with a cathode around a central anode. A source of magnetic field with closely spaced poles is formed around a central region of the cathode so that the most intense region of the magnetic field is a torus on the inside of the cathode and the field at the anode is weak. A torus of plasma can be formed near the inside surface of the cathode which can be coated with solid source material. An ion beam can be extracted through an aperture in the cathode.

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: 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: 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: A system for controlling the spin rate of a sample in an NMR spectrometer using an ON/OFF valve controlled by a digital system to regulate flow of a gas between a source and a sample spinner. A spin rate detector supplies rate information to the digital control. The digital control varies the ON/OFF valve duty cycle to control the spin rate.

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.

Abstract: Refractory metals or ceramics are diffusion bonded or densified by assembling the workpieces to be bonded, wrapping the assembly with carbon yarn, heating the wrapped assembly, cooling the assembly and unwrapping. The expansion of the workpieces together with the shrinking of the carbon yarn produces tremendous pressures which cause bonding and densifying of the workpiece.

Abstract: In order to compensate for worn or distorted wafer cassettes and missing wafers, the cassette of wafers is scanned through a beam. The timing of the interruptions of the beam is used to inventory the wafers present and measure the exact position of each wafer relative to the base of the cassette.

Abstract: A chemical vapor deposition apparatus includes a gas mixing chamber and a water-cooled reaction chamber with adjustable water-cooled baffle between them. A wafer is clamped face down to a chuck and an inert gas such as helium is forced between the chuck and the wafer to insure proper heat conduction from chuck to wafer. The chuck can be radiantly heated from above and operated in a plasma-enhanced mode. A wafer loading apparatus driven by a computer is isolated by a loadlock during deposition to enhance cleanliness. The chamber can be plasma cleaned to reduce downtime.

Abstract: A wafer processing system including wafer handling arms incorporated into vacuum isolation valves is described. A loadlock with elevator and optical sensors is used to inventory and position a cassette of wafers. The wafers in the cassette can be randomly accessed. A computer is used to control the system according to a task status table independent of time sequence.

Abstract: A system for controlling the spin rate of a sample in an NMR spectrometer using an ON/OFF valve controlled by a digital system to regulate flow of a gas between a source and a sample spinner. A spin rate detector supplies rate information to the digital control. The digital control varies the ON/OFF valve duty cycle to control the spin rate.

Abstract: An apparatus for micropositioning an X-ray lithography mask has but a single stage plate for supporting the mask, three piezoelectric transducers for moving the stage plate in the X-Y plane, and three flexure assemblies located equiangularly around the stage plate for supporting the stage plate and for moving the stage plate in the Z-axis. The flexure assemblies each include a single piezoelectric transducer and various flex strips to allow relative motion of the stage plate to occur smoothly in all six of the possible degrees of freedom.