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Scanning electron beam probes VLSI chips
World Abstracts on Microelectronics and Reliability contacts which havca low resistance that remains low with agc. Polishing and etching procedures for achieving satisfactory simple platinum-plated contacts are described. Significant improvement, yielding lower resistance and Iongcr life contacts, has becn cffected by a procedure involving implantation of silver at three ion energies followed by a single pulse anneal with ruby laser radiation. Also dcscribcd is a copper-gallium alloy which allowed convenient and easy bonding, at temperatures just above room temperature, of PbTe diode lasers to heat sinks.
Modified SEM depicts operation of dense chips. KEV1NSMITH. Electronics p. 73 ~30 June 1981 ). Fixture turns electron beam of scanning electron microscope into probe that samples VLSI voltage waveforms.
Laser crystallization of amorphoussilicium thin-films. J. F. PERAY,J. ICOLEand M. CROSET. Revue Technique ThomsonCSF 13 (2) 227 (June 1981 ) (in French). This paper is related to pulsed-laser-crystallization of amorphous silicon thin film deposited onto amorphous substrates. We develop in the text a macroscopic modelling of optical absorption process and laser energy redistribution, in function of silicon deposition method and the substrate nature, according to the thermal hypothesis. The laser used was a Nd-YAG from Quantel Gram spot size, 20ns FWHM). We have shown, by using several characterization methods (RBS, ESR, Raman...) that crystallization occurs from bulk to surface, over a depth depending on deposited energy E, providing that the E value would be higher than a threshold value. Grain size of polycrystalline silicon obtained by laser irradiation depends on substrate thermal conductivity and heat capacity. Silicon layers obtained after laser annealing exhibit high optical absorption properties and good electrical conductivity making up this material suitable for photovoltaic conversion of solar energy. GaAs Hall devices produced by local ion implantation. E. PETTENPAUL,J. HUBER, H. WEDLICH, W. FLOSSMANNand U. VON BORCKE.Solid-St-. Electron. 24 (8) 781 (1981). GaAs Hall devices were produced by complete planar technology using two selective silicon ion implantation steps. The fundamental characteristics of these devices with respect to reproducible implantation dose and geometry of cross-shaped elements
143
are obtained both by experiment and calculation. The prominent properties of the GaAs Hall elements presented are high sensitivity and linearity, small temperature dependence of sensitivity and resistance, and low residual voltage.
Lasers
automate I~-board inspection. LINDA LOWE. Electronics p. 96 114 July 1981). Systems aim to eliminate field failure of boards that have passed makers' tests and inspections. Scanning electron beam probes VLSI chips. PETER FAZEKAS, HANs-PETER FEUERBAUM and ECKHARD WOLEGANG. Electronics p. 105 (14 July 1981 ). Functional analysis of'very large-scale integrated circuits is beginning to take a new form: a focused electron beam scanning the entire surface of the chip makes noncontacting, nonloading measurements and maps the IC's logic functions. The scanning electron beam implements the established voltage-contrast technique--relying on areas of lightness and darkness in the resulting chip image to represent logic voltage levels--but new test techniques turn the formerly static technique into a dynamic measurement process. By coordinating the beam's scan rate with the clock signals in an energized device under test, it is possible to display the signals in the form of logic state maps superimposed on the IC image. Thereby a comprehensive analysis of an IC can be made as never before. The test setup adds a logic analyzer to the sampling electron microscope, itself a special version of a scanning electron microscope. Thus digital signals can be measured--but analog waveforms also can be checked, and the test techniques can be applied to all types of ICs.
Carrier mobility in laser-annealed silicon-on-sapphire films. E. W. MAB¥and C. P. Wo. RCA Review42, 118 (March 1981 ). Average carrier mobilities determined by Hall-resistivity measurements are reported for ion-implanted silicon-onsapphire (SOS) films that were annealed with a pulsed NdYAG laser. The results demonstrate significant mobility improvement when laser annealing follows ion implantation. Although less impressive, mobility improvements are also realized for an SOS processing sequence in which laser annealing precedes ion implantation and furnace annealing.
Modified SEM depicts operation of dense chips. KEV1NSMITH. Electronics p. 73 ~30 June 1981 ). Fixture turns electron beam of scanning electron microscope into probe that samples VLSI voltage waveforms.
Laser crystallization of amorphoussilicium thin-films. J. F. PERAY,J. ICOLEand M. CROSET. Revue Technique ThomsonCSF 13 (2) 227 (June 1981 ) (in French). This paper is related to pulsed-laser-crystallization of amorphous silicon thin film deposited onto amorphous substrates. We develop in the text a macroscopic modelling of optical absorption process and laser energy redistribution, in function of silicon deposition method and the substrate nature, according to the thermal hypothesis. The laser used was a Nd-YAG from Quantel Gram spot size, 20ns FWHM). We have shown, by using several characterization methods (RBS, ESR, Raman...) that crystallization occurs from bulk to surface, over a depth depending on deposited energy E, providing that the E value would be higher than a threshold value. Grain size of polycrystalline silicon obtained by laser irradiation depends on substrate thermal conductivity and heat capacity. Silicon layers obtained after laser annealing exhibit high optical absorption properties and good electrical conductivity making up this material suitable for photovoltaic conversion of solar energy. GaAs Hall devices produced by local ion implantation. E. PETTENPAUL,J. HUBER, H. WEDLICH, W. FLOSSMANNand U. VON BORCKE.Solid-St-. Electron. 24 (8) 781 (1981). GaAs Hall devices were produced by complete planar technology using two selective silicon ion implantation steps. The fundamental characteristics of these devices with respect to reproducible implantation dose and geometry of cross-shaped elements
143
are obtained both by experiment and calculation. The prominent properties of the GaAs Hall elements presented are high sensitivity and linearity, small temperature dependence of sensitivity and resistance, and low residual voltage.
Lasers
automate I~-board inspection. LINDA LOWE. Electronics p. 96 114 July 1981). Systems aim to eliminate field failure of boards that have passed makers' tests and inspections. Scanning electron beam probes VLSI chips. PETER FAZEKAS, HANs-PETER FEUERBAUM and ECKHARD WOLEGANG. Electronics p. 105 (14 July 1981 ). Functional analysis of'very large-scale integrated circuits is beginning to take a new form: a focused electron beam scanning the entire surface of the chip makes noncontacting, nonloading measurements and maps the IC's logic functions. The scanning electron beam implements the established voltage-contrast technique--relying on areas of lightness and darkness in the resulting chip image to represent logic voltage levels--but new test techniques turn the formerly static technique into a dynamic measurement process. By coordinating the beam's scan rate with the clock signals in an energized device under test, it is possible to display the signals in the form of logic state maps superimposed on the IC image. Thereby a comprehensive analysis of an IC can be made as never before. The test setup adds a logic analyzer to the sampling electron microscope, itself a special version of a scanning electron microscope. Thus digital signals can be measured--but analog waveforms also can be checked, and the test techniques can be applied to all types of ICs.
Carrier mobility in laser-annealed silicon-on-sapphire films. E. W. MAB¥and C. P. Wo. RCA Review42, 118 (March 1981 ). Average carrier mobilities determined by Hall-resistivity measurements are reported for ion-implanted silicon-onsapphire (SOS) films that were annealed with a pulsed NdYAG laser. The results demonstrate significant mobility improvement when laser annealing follows ion implantation. Although less impressive, mobility improvements are also realized for an SOS processing sequence in which laser annealing precedes ion implantation and furnace annealing.