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Effects of process variables on thick-film resistors
122
WORLD
ABSTRACTS
ON MICROELECTRONICS
radiation damage of fast neutrons to experimental GaAs junction field-effect transistors (J-FETs). Active and passive GaAs devices fabricated from epitaxial n-type material in a doping range from 10 to the power 16 to 10 to the power 17 cm s were exposed to a fast-neutron fluenee (E greater than 10 keV) in the range from 10 to the power 15 to 10 to the power 16 n/cm. T h e GaAs J - F E T s have a nominal channel length of 5 micron (i.e. maximum frequency of oscillation between 4 and 6 GHz). T h e passive devices are four-point probe structures and passive J - F E T structures without a pn-junction gate. Pre-irradiation and post-irradiation measurements are correlated with theory. A n extended unipolar transistor theory which describes the operation of F E T s in the hot-electron range was applied to predict and correlate the degradation characteristics of devices exposed to fast neutrons. Parasitic device elements are identified and their influence on determination of normalized degradation parameters is discussed. A comparison between Si
AND
RELIABILITY
and GaAs J - F E T s of equivalent channel doping is presented. A n o m a l o u s forward characteristics o f a m e t a l - t h i n e p i t a x i a l s i l i c o n j u n c t i o n . C. E. BURTON, W. M. PORTNOY and H. M. LEVy. Solid St. Electron. 14 (1971), p. 1071. T h e forward current-voltage characteristics of metal-thin epitaxial silicon diodes were measured for the contact metals titanium, cerium, molybdenum and vanadium. T h e measurements were made for circular junctions, with diameters varying between 0"89× 10-3 cm and 4 . 6 × 1 0 -3 cm, at temperatures between --74 and 150°C. It was found that. the diodes did not obey Schottky theory, but that their current-voltage characteristics contained a leakage component that persisted until high forward biases had been attained. T h e behavior of the leakage component was described in terms of the degree of epitaxial depletion. At high forward biases, Schottky behavior was apparently restored.
8. THICK- AND THIN-FILM COMPONENTS, CIRCUITS AND MATERIALS Effects of process variables on t h i c k - f i l m r e s i s t o r s . D. W. WILLIAMS. Proc. 21st Electron. Compon. Conf., Washington D.C., U.S.A., 10-12 May (1971), p. 454. T h e advances being made in thick-film tcehnology make it difficult to update processes to be consistent with state-of-the-art materials. T h e purpose and intent of this paper is to evaluate what is considered a process specification for resistors. Printing, drying and firing parameters will be varied to an extent that an operator on any given day could change any one of the steps of the resistor specification. T h e parameters that will be varied are squeegee height, screen breakaway distance, squeegee velocity, drying and firing profiles. Due to the amount of data accumulated, this paper will be limited to the as-fired value of the resistor and the T C R of the resistor. T h e author recognizes that the results of this experiment are per one manufacturer's paste and may not necessarily pertain to other manufacturer's material.
Electron m i c r o p r o b e a n a l y s i s o f I-IgTe thin films. A. SZUMMER and S. A. IGNATOWICZ. Electron. Technol. 4, No. 1/2 (1971), p. 227. T h e paper deals with the investigation of the chemical composition of H g T e thin films obtained by evaporation of polycrystalline HgTe solid material. X-ray microanalysis by means of an electron microprobe (model JXA-3A) has been undertaken for the quantitative determination of the homogeneity and a stoiehiometry of films. T h e results are compared with those obtained from the colorimetric method. Good agreement between both methods has been found. Interconnectionn w i t h gold b e a m lemdL J. M. TACKEN and L. H. RAPMUND. 1SHM (UK) International Hybrid Microelectronics Conf., London, 19 and 20 April (1971). A self-adjusting bonding tool for connecting beam leaded chips with gold conductors on a substrate
is described. With this tool all leads are bonded in one stroke. This tool can also be used for connecting a chip with the test circuitry for testing the device. Although the heat resistance per lead is relatively high, the total heat resistance of many leads is low enough for practical heat dissipations. ¢ r h i c k - f i l m filter for television signals. J. R. CORKHILL and M. J. MARTIN. Royal Aircraft Est., Faroborough, Hants, August (1970), pp. 28. BR-21614, RAE-TR-70142. T h e performance and construction of a thick-film filter for television signals is described. A computer program for linear analysis has been used to analyse the filter and the computed results are compared with measured results. Details are also given of inductor design and performance. A p o t e n t i o m e t e r n e t w o r k m o d u l e . J. H. POWERS, Jr. "and J. H. BRANGACCIO. Proc. 21st Electron. Compon. Conf., Washington D.C., U.S.A., 10-12 May (1971), p. 379. A study was conducted on modules incorporating a thick-film adjustable resistor divider network. Such a device offers potential reductions in cost and size over conventional discrete component approaches while providing superior performance due to the inherent tracking characteristics of a film resistor network. T h e application, design and performance characterization of such "potentiometer network modules" are discussed.
Flatness a n d surface roughness of s o m e c o m m o n f i l m s u l ~ r a t e m a t e r / a l s . R. M. ANDERSON and G. W. NEUDXCK. J. Vac. S~. Technol. 8, No. 2, March/April (1971), p. 454. T h e flatness and roughness of nine comm o n substrate materials (quartz flat, Coming 7059 glass, C o m i n g 0211 glass, soft glass, AISiMag 614, AISiMag 614 with 743 glaze, AISiMag 772, mechanically polished silicon and chemically polished silicon) are reported.
WORLD
ABSTRACTS
ON MICROELECTRONICS
radiation damage of fast neutrons to experimental GaAs junction field-effect transistors (J-FETs). Active and passive GaAs devices fabricated from epitaxial n-type material in a doping range from 10 to the power 16 to 10 to the power 17 cm s were exposed to a fast-neutron fluenee (E greater than 10 keV) in the range from 10 to the power 15 to 10 to the power 16 n/cm. T h e GaAs J - F E T s have a nominal channel length of 5 micron (i.e. maximum frequency of oscillation between 4 and 6 GHz). T h e passive devices are four-point probe structures and passive J - F E T structures without a pn-junction gate. Pre-irradiation and post-irradiation measurements are correlated with theory. A n extended unipolar transistor theory which describes the operation of F E T s in the hot-electron range was applied to predict and correlate the degradation characteristics of devices exposed to fast neutrons. Parasitic device elements are identified and their influence on determination of normalized degradation parameters is discussed. A comparison between Si
AND
RELIABILITY
and GaAs J - F E T s of equivalent channel doping is presented. A n o m a l o u s forward characteristics o f a m e t a l - t h i n e p i t a x i a l s i l i c o n j u n c t i o n . C. E. BURTON, W. M. PORTNOY and H. M. LEVy. Solid St. Electron. 14 (1971), p. 1071. T h e forward current-voltage characteristics of metal-thin epitaxial silicon diodes were measured for the contact metals titanium, cerium, molybdenum and vanadium. T h e measurements were made for circular junctions, with diameters varying between 0"89× 10-3 cm and 4 . 6 × 1 0 -3 cm, at temperatures between --74 and 150°C. It was found that. the diodes did not obey Schottky theory, but that their current-voltage characteristics contained a leakage component that persisted until high forward biases had been attained. T h e behavior of the leakage component was described in terms of the degree of epitaxial depletion. At high forward biases, Schottky behavior was apparently restored.
8. THICK- AND THIN-FILM COMPONENTS, CIRCUITS AND MATERIALS Effects of process variables on t h i c k - f i l m r e s i s t o r s . D. W. WILLIAMS. Proc. 21st Electron. Compon. Conf., Washington D.C., U.S.A., 10-12 May (1971), p. 454. T h e advances being made in thick-film tcehnology make it difficult to update processes to be consistent with state-of-the-art materials. T h e purpose and intent of this paper is to evaluate what is considered a process specification for resistors. Printing, drying and firing parameters will be varied to an extent that an operator on any given day could change any one of the steps of the resistor specification. T h e parameters that will be varied are squeegee height, screen breakaway distance, squeegee velocity, drying and firing profiles. Due to the amount of data accumulated, this paper will be limited to the as-fired value of the resistor and the T C R of the resistor. T h e author recognizes that the results of this experiment are per one manufacturer's paste and may not necessarily pertain to other manufacturer's material.
Electron m i c r o p r o b e a n a l y s i s o f I-IgTe thin films. A. SZUMMER and S. A. IGNATOWICZ. Electron. Technol. 4, No. 1/2 (1971), p. 227. T h e paper deals with the investigation of the chemical composition of H g T e thin films obtained by evaporation of polycrystalline HgTe solid material. X-ray microanalysis by means of an electron microprobe (model JXA-3A) has been undertaken for the quantitative determination of the homogeneity and a stoiehiometry of films. T h e results are compared with those obtained from the colorimetric method. Good agreement between both methods has been found. Interconnectionn w i t h gold b e a m lemdL J. M. TACKEN and L. H. RAPMUND. 1SHM (UK) International Hybrid Microelectronics Conf., London, 19 and 20 April (1971). A self-adjusting bonding tool for connecting beam leaded chips with gold conductors on a substrate
is described. With this tool all leads are bonded in one stroke. This tool can also be used for connecting a chip with the test circuitry for testing the device. Although the heat resistance per lead is relatively high, the total heat resistance of many leads is low enough for practical heat dissipations. ¢ r h i c k - f i l m filter for television signals. J. R. CORKHILL and M. J. MARTIN. Royal Aircraft Est., Faroborough, Hants, August (1970), pp. 28. BR-21614, RAE-TR-70142. T h e performance and construction of a thick-film filter for television signals is described. A computer program for linear analysis has been used to analyse the filter and the computed results are compared with measured results. Details are also given of inductor design and performance. A p o t e n t i o m e t e r n e t w o r k m o d u l e . J. H. POWERS, Jr. "and J. H. BRANGACCIO. Proc. 21st Electron. Compon. Conf., Washington D.C., U.S.A., 10-12 May (1971), p. 379. A study was conducted on modules incorporating a thick-film adjustable resistor divider network. Such a device offers potential reductions in cost and size over conventional discrete component approaches while providing superior performance due to the inherent tracking characteristics of a film resistor network. T h e application, design and performance characterization of such "potentiometer network modules" are discussed.
Flatness a n d surface roughness of s o m e c o m m o n f i l m s u l ~ r a t e m a t e r / a l s . R. M. ANDERSON and G. W. NEUDXCK. J. Vac. S~. Technol. 8, No. 2, March/April (1971), p. 454. T h e flatness and roughness of nine comm o n substrate materials (quartz flat, Coming 7059 glass, C o m i n g 0211 glass, soft glass, AISiMag 614, AISiMag 614 with 743 glaze, AISiMag 772, mechanically polished silicon and chemically polished silicon) are reported.