摘要:
Disclosed is a method of welding a temperature-sensing thermocouple to a silicon wafer for sensing the temperature of the wafer during rapid thermal processing using TIG welding and/or electron-beam welding. In one embodiment, a ball of silicon is formed on the bead at one end of a thermocouple by placing the thermocouple on a silicon chip and then melting the silicon chip with a TIG welder. The ball and thermocouple are then placed on the surface of a silicon wafer and the ball and surface are then melted whereby the ball of silicon flows into the silicon wafer. In placing the thermocouple on an edge portion of a silicon wafer, the wafer is supported on a tantalum plate with the edge portion of the wafer extending beyond the plate. A molybdenum sheet is positioned on the top surface of the wafer with the edge portion of the wafer exposed. A TIG arc is established with the molybdenum layer and then the arc is moved to the edge portion of the wafer for melting the silicon. In attaching the thermocouple on the silicon wafer other than on an edge portion, electron-beam welding is employed. An electron beam at low power is focused on the ball of silicon, and then the power of the electron beam is increased while the beam is pulsed so that the ball and adjacent silicon wafer are melted.
摘要:
The present invention comprises a method of fabricating devices and circuits employing at least one heteroepitaxial layer under strain. The thickness of the heteroepitaxial layer is more than two times the calculated equilibrium critical thickness for an uncapped heteroepitaxial layer upon a crystalline substrate, based on previously known equilibrium theory for the uncapped layer. Subsequent to growth of the heteroepitaxial layer, the structure is processed at temperatures higher than the growth temperature of the heteroepitaxial layer.The strained heteroepitaxial layer (second layer) is epitaxially grown upon the surface of a first, underlaying crystalline layer, creating a heterojunction. Subsequently a third crystalline layer is deposited or grown upon the major exposed surface of the second, strained heteroepitaxial layer. The preferred manner of growth of the third crystalline layer is epitaxial growth. The composition of the third crystalline layer must be such that upon deposition or growth, the third layer substantially continuously binds to the heteroepitaxial structure of the second layer. Subsequent to growth of the at least three layer structure, the structure is processed at temperatures in excess of the growth temperature of the second heteroepitaxial layer. Presence of the third crystalline layer prevents the generation of a substantial amount of misfit dislocations between the first crystalline layer substrate and the second heteroepitaxial layer.
摘要:
Semiconductor device performance is improved via a gate structure having a tunable effective workfunction and reduced gate depletion effects. According to an example embodiment, the design threshold voltage of a semiconductor device is adjusted in a manner that includes providing a gate having a workfunction that enables operation of the semiconductor device at a selected voltage. The gate is formed having two different conductive materials with different electric workfunctions that both significantly contribute to the overall workfunction of the gate. The relative composition, thickness, and arrangement of each of the two conductive materials is selected to attain a gate electrode workfunction that is different than the workfunctions of each of the two layers and that sets the threshold voltage of the semiconductor device. The adjustability of the effective workfunction of the gate electrode can be applied to a variety of semiconductor devices. The ability to reduce gate depletion effects also provides enhanced device current drive.
摘要:
Several methods are disclosed for minimizing the number of defects or misfit locations in a SiGe layer selectively or non-selectively deposited on a partially oxide masked Si substrate.
摘要:
Improved devices with silicon to SiGe alloy heterojunctions are provided for in accordance with the following discoveries. X-ray topography and transmission electron microscopy were used to quantify misfit-dislocation spacings in as-grown Si.sub.1-x Ge.sub.x films formed by Limited Reaction Processing (LRP), which is a chemical vapor deposition technique. These analysis techniques were also used to study dislocation formation during annealing of material grown by both LRP and by molecular beam epitaxy (MBE). The thickness at which misfit dislocations first appear in as-grown material was similar for both growth techniques. The thermal stability of capped and uncapped films was also investigated after rapid thermal annealing in the range of 625.degree. to 1000.degree. C. Significantly fewer misfit dislocations were observed in samples containing an epitaxial silicon cap. Some differences in the number of misfit dislocations generated in CVD and MBE films were observed after annealing uncapped layers at temperatures between 625.degree. and 825.degree. C.
摘要:
A rapid thermal heating apparatus including an evacuable chamber having a window, a plurality of radiant energy sources and reflectors associated with the radiant energy sources. The radiant energy sources are disposed outside of the chamber and positioned adjacent to the window. They have a central longitudinal axis that extends in a substantially perpendicular direction relative to the window. The reflectors direct radiant energy through the window to radiate predetermined regions of a backside surface of a substrate in the chamber. The reflectors extend along a major portion of the longitudinal axis of the radiant energy sources. The substrate sits on a support in the chamber, and a source of processing gas, including a gas inlet manifold, is provided for passing processing gas to a frontside surface of the substrate.
摘要:
A rapid thermal heating apparatus in which lamps are disposed in a plurality of light pipes arranged to illuminate and supply heat to a substrate. The light pipes are positioned so that the illumination patterns overlap. The energy supplied to the lamps is controlled to provide a predetermined heating pattern to the substrate. A liquid cooled window cooperates with the light pipes to transmit energy to a wafer disposed in an evacuated chamber.
摘要:
A programmable read only memory (PROM) includes a first plurality of conductive lines, a second plurality of conductive lines and polycrystalline silicon material therebetween. At the crossing points of the first and second plurality of lines doped regions are provided in the polycrystalline silicon in contact with a second line and which extend at least partially through the material. To provide a diode interconnect at any crossing point, the associated region is irradiated by a laser beam to either cause diffusion of dopant atoms to the underlaying conductive line or activate implanted ions, thereby electrically interconnecting the first and second lines through a diode. The PROM is readily fabricated as part of a monolithic integrated circuit or electrical array and can be programmed after completion of the fabrication process.
摘要:
Low resistance, doped polycrystalline semiconductor connection patterns are fabricated by scanning a doped polycrystalline layer with a laser beam thereby increasing the crystal grain size, reducing defects in the grains, increasing charge carrier mobility and as a result reducing material resistivity. Semiconductor devices having increased circuit density and speed are realized through use of laser annealed polycrystalline semiconductor resistors, contacts and interconnections.
摘要:
A rapid thermal heating apparatus in which lamps are disposed in a plurality of light pipes arranged to illuminate and supply heat to a substrate. The light pipes are positioned so that the illumination patterns overlap. The energy supplied to the lamps is controlled to provide a predetermined heating pattern to the substrate. A liquid cooled window cooperates with the light pipes to transmit energy to a wafer disposed in an evacuated chamber.