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Particle-beam fabrication and ‘in situ’ processing of integrated circuits
942
World Abstracts on Microelectronics and Reliability 7. S E M I C O N D U C T O R
INTEGRATED
CIRCUITS,
The application of radioanalytieal methods in semiconductor technology. E. W. HAAS and R. HOFMANN.Solid-St. Electron. 30 (3), 329 (1987). For about 25 years the radioanalytical activation analysis, autoradiography and radiotracer technique have been widely used in the development of semiconductor technology. The advantages of these techniques are its high detection sensitivity by simultaneous determination of a broad spectrum of elements in a wide range of materials, making visible impurity inhomogenities and element distributions with a resolution down to a few micrometers. The latest results from analyses of semiconductor material development, device fabrication and of auxiliary materials used in"this process are presented. Properties of amorphous CdS-crystailine Si junctions. D.
8. T H I C K -
AND
THIN-FILM
COMPONENTS,
Further studies of the interactions between thick film resistors and dielectrics. BARBARA BOBER and KEITH PITT. Microelectron. J. 18 (I), 35 (1987). Previous work has demonstrated that there is an interchange of constituents between the films when thick films are fired on dielectric layers. This paper extends the study from ruthenium dioxide
9. E L E C T R O N ,
ION
AND
An optimal annealing technique for OHMIC contacts to ionimplanted n-layers in semMnsuiating indium phosphide. K. P PANDE, E. MARTIN, D. GUTIERREZ and O. AINA. Solid-St. Electron. 30 (3), 253 (1987). An optimal annealing process was developed for sintering A u - G e ohmic contacts to ion-implanted semi-insulating InP substrates. Contacts were annealed using a standard furnace, graphite strip heater and a lamp annealer. Alloying at 375°C for 3 min was found to be most suitable for achieving good contact morphology and lowest contact resistivity. Of the three techniques, the lamp annealing technique was found to give the best results when contacts were annealed under a SiO 2 cap. Contact resistivity as low as 8 x 10-6cm 2 was obtained for ion-implanted n + layers in semi-insulating InP. Reactive ion etching of direct-write metallisation patterns. RUTH E. BUCKNALL and PETER J. ASTELL-BURT. Microelectron. J. lg (1), 49 (1987). Optical lithography has indisputably been the leading integrated circuit pattern defining technique for many years. It is essentially two steps. First, the design and fabrication of the optical mask, which is both costly and time consuming, and secondly, the exposure
AND
MATERIALS
NESHEVA. Solid-St. Electron. 30 (2), 173 (1987). Junctions between amorphous a-CdS and crystalline n-Si have been prepared. It is found that the junctions are rectifying with a coefficient kr = 102-103 at room temperature. The temperature dependence of k,, the J - V characteristics and the spectral intensity dependence of the photocurrent have been measured. The results are interpreted on the basis of carrier injection from c-Si to a-CdS and the assumption that C? states in a-CdS define the reverse current flow. An energy band diagram of the heterojunction is proposed.
Gaseous impurity effects in silicon epitaxy. RAYMOND P. ROBERGE, ARTHUR W. FRANCIS JR, STEPHEN M. FISHER and SHERMANC. SCHMITZ. Semiconductor int., 77 (January 1987). Investigation has quantified the pronounced effect of trace oxygen on wafer surface haze and defect density.
HYBRID
CIRCUITS
AND
MATERIALS
based resistors to those based on barium ruthenate. It shows that, here also, the reactions are much less marked on the filled glaze D P 9950 than on the crystallising D P 9429 and that electrical changes have a similar relationship. Plots are given of the change of chemical constitution over the cross sections of several different resistors/dielectric combinations.
LASER
Particle-beam fabrication and 'in situ' processing of integrated circuits. ANDREW J. STECKL. Proc. IEEE 74 (12), 1753 (1986). Particle beams, in their broadest context, have become the most common tools in the kit of the IC process engineer. In this paper the general characteristics of particle-beam technologies are systematically classified and critical applications issues are outlined. The uses of ion, electron, and photon beams for various processes (e.g. thin-film deposition, lithography, etching, doping) are reviewed and critical issues are highlighted. The feasibility of integrating several advanced beam processes to achieve a totally in situ process is discussed. Particulate contamination in "clean"-room environment and under vacuum conditions is addressed and related to chip defects and yield. The relative advantages, in terms of facility and operating cost, flexibility, device performance, of an in situ process are considered.
DEVICES
BEAM
TECHNIQUES
of the wafer, covered with a layer of light sensitive photoresist, to ultra violet light shone through the mask. The method is ideal for large scale production because once the expensive masking process has been carried out, an unlimited number of wafers may be patterened [sic] at very low cost to the producer.
Reactive ion etching of AlSiCu alloy films. STEPHEN M. PEARSON, MICHAEL A. WILDERS and ANDREW A. CHAMBERS. Semiconductor int., 97 (February 1987). Reactive ion etching of A1SiCu metalization in SIC14 gas plasma has proved useful in removing copper residue. Advanced lithographies: finding a niche. PIETER BURGGRAAF. Semiconductor int., 48 (February 1987). E-beam, X-ray and ion beam lithographies are emerging into niches, including compatibility with photolithography. Self-consistent analysis of gain-guided triple stripe lasers. TRIBHAWAN KUMAR. Solid-St. Electron. 30 (1), 21 (1987). A considerable near field shift in DH triple stripe lasers is demonstrated by tailoring the applied bias on the stripes. No closed form solution for the current spreading in the passive layer is assumed. The two dimensional Laplace's equation in the passive layer, which is coupled with the diffusion equation of carriers in the active layer via the variation of the separation of quasi-Fermi levels, is solved consistently. Both the bimolecular and stimulated recombinations are included in the diffusion equation. The stimulated recombination determination couples the wave equation with the rest of the problem which is treated self-consistently. The paper highlights the influence of the different applied potentials on the strips, the electrode spacing and the diffusion constant on the optical behaviour of the device. A travelling-wave rate equation analysis for semiconductor lasers. Y. L. TONG and J. E. CARROLL.Solid-St. Electron. 30 (1), 13 1(987). A travelling-wave rate equation model for the investigation of the transient effects in a semiconductor laser
World Abstracts on Microelectronics and Reliability 7. S E M I C O N D U C T O R
INTEGRATED
CIRCUITS,
The application of radioanalytieal methods in semiconductor technology. E. W. HAAS and R. HOFMANN.Solid-St. Electron. 30 (3), 329 (1987). For about 25 years the radioanalytical activation analysis, autoradiography and radiotracer technique have been widely used in the development of semiconductor technology. The advantages of these techniques are its high detection sensitivity by simultaneous determination of a broad spectrum of elements in a wide range of materials, making visible impurity inhomogenities and element distributions with a resolution down to a few micrometers. The latest results from analyses of semiconductor material development, device fabrication and of auxiliary materials used in"this process are presented. Properties of amorphous CdS-crystailine Si junctions. D.
8. T H I C K -
AND
THIN-FILM
COMPONENTS,
Further studies of the interactions between thick film resistors and dielectrics. BARBARA BOBER and KEITH PITT. Microelectron. J. 18 (I), 35 (1987). Previous work has demonstrated that there is an interchange of constituents between the films when thick films are fired on dielectric layers. This paper extends the study from ruthenium dioxide
9. E L E C T R O N ,
ION
AND
An optimal annealing technique for OHMIC contacts to ionimplanted n-layers in semMnsuiating indium phosphide. K. P PANDE, E. MARTIN, D. GUTIERREZ and O. AINA. Solid-St. Electron. 30 (3), 253 (1987). An optimal annealing process was developed for sintering A u - G e ohmic contacts to ion-implanted semi-insulating InP substrates. Contacts were annealed using a standard furnace, graphite strip heater and a lamp annealer. Alloying at 375°C for 3 min was found to be most suitable for achieving good contact morphology and lowest contact resistivity. Of the three techniques, the lamp annealing technique was found to give the best results when contacts were annealed under a SiO 2 cap. Contact resistivity as low as 8 x 10-6cm 2 was obtained for ion-implanted n + layers in semi-insulating InP. Reactive ion etching of direct-write metallisation patterns. RUTH E. BUCKNALL and PETER J. ASTELL-BURT. Microelectron. J. lg (1), 49 (1987). Optical lithography has indisputably been the leading integrated circuit pattern defining technique for many years. It is essentially two steps. First, the design and fabrication of the optical mask, which is both costly and time consuming, and secondly, the exposure
AND
MATERIALS
NESHEVA. Solid-St. Electron. 30 (2), 173 (1987). Junctions between amorphous a-CdS and crystalline n-Si have been prepared. It is found that the junctions are rectifying with a coefficient kr = 102-103 at room temperature. The temperature dependence of k,, the J - V characteristics and the spectral intensity dependence of the photocurrent have been measured. The results are interpreted on the basis of carrier injection from c-Si to a-CdS and the assumption that C? states in a-CdS define the reverse current flow. An energy band diagram of the heterojunction is proposed.
Gaseous impurity effects in silicon epitaxy. RAYMOND P. ROBERGE, ARTHUR W. FRANCIS JR, STEPHEN M. FISHER and SHERMANC. SCHMITZ. Semiconductor int., 77 (January 1987). Investigation has quantified the pronounced effect of trace oxygen on wafer surface haze and defect density.
HYBRID
CIRCUITS
AND
MATERIALS
based resistors to those based on barium ruthenate. It shows that, here also, the reactions are much less marked on the filled glaze D P 9950 than on the crystallising D P 9429 and that electrical changes have a similar relationship. Plots are given of the change of chemical constitution over the cross sections of several different resistors/dielectric combinations.
LASER
Particle-beam fabrication and 'in situ' processing of integrated circuits. ANDREW J. STECKL. Proc. IEEE 74 (12), 1753 (1986). Particle beams, in their broadest context, have become the most common tools in the kit of the IC process engineer. In this paper the general characteristics of particle-beam technologies are systematically classified and critical applications issues are outlined. The uses of ion, electron, and photon beams for various processes (e.g. thin-film deposition, lithography, etching, doping) are reviewed and critical issues are highlighted. The feasibility of integrating several advanced beam processes to achieve a totally in situ process is discussed. Particulate contamination in "clean"-room environment and under vacuum conditions is addressed and related to chip defects and yield. The relative advantages, in terms of facility and operating cost, flexibility, device performance, of an in situ process are considered.
DEVICES
BEAM
TECHNIQUES
of the wafer, covered with a layer of light sensitive photoresist, to ultra violet light shone through the mask. The method is ideal for large scale production because once the expensive masking process has been carried out, an unlimited number of wafers may be patterened [sic] at very low cost to the producer.
Reactive ion etching of AlSiCu alloy films. STEPHEN M. PEARSON, MICHAEL A. WILDERS and ANDREW A. CHAMBERS. Semiconductor int., 97 (February 1987). Reactive ion etching of A1SiCu metalization in SIC14 gas plasma has proved useful in removing copper residue. Advanced lithographies: finding a niche. PIETER BURGGRAAF. Semiconductor int., 48 (February 1987). E-beam, X-ray and ion beam lithographies are emerging into niches, including compatibility with photolithography. Self-consistent analysis of gain-guided triple stripe lasers. TRIBHAWAN KUMAR. Solid-St. Electron. 30 (1), 21 (1987). A considerable near field shift in DH triple stripe lasers is demonstrated by tailoring the applied bias on the stripes. No closed form solution for the current spreading in the passive layer is assumed. The two dimensional Laplace's equation in the passive layer, which is coupled with the diffusion equation of carriers in the active layer via the variation of the separation of quasi-Fermi levels, is solved consistently. Both the bimolecular and stimulated recombinations are included in the diffusion equation. The stimulated recombination determination couples the wave equation with the rest of the problem which is treated self-consistently. The paper highlights the influence of the different applied potentials on the strips, the electrode spacing and the diffusion constant on the optical behaviour of the device. A travelling-wave rate equation analysis for semiconductor lasers. Y. L. TONG and J. E. CARROLL.Solid-St. Electron. 30 (1), 13 1(987). A travelling-wave rate equation model for the investigation of the transient effects in a semiconductor laser