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Polymer-monomer conversion in anthracene thin films as a switching and memory device
142
World Abstracts on Microelectronics and Reliability
GalnAs and GalnAsP materials on lnP substrates have been developed. These two expitaxial growth techniques in the vapor phase, namely the hydrides method with multichamber reactor and the organometallics method at low pressure, make it possible to obtain high-quality materials for microwave and optronic applications. Diamond structure versus Wurtzite structure for silicon. J. SANCHEZ-DEHESA, J. A. VERGES and C. TEIEDOR. Solid St. Comraun. 38, 871 (1981). A calculation of the total energy of silicon in crystal structures with tetrahedral coordination is self-consistently performed in a Iocalised scheme. The behaviour of the total energy is similar to the one obtained with a rather sophisticated pseudopotential within a very different computational framework. We show that the change in the electrostatic energy is dominant over the remainder contributions, which makes it responsible for the stability of diamond with respect to wurtzite structure. Both the band structure and the interaction between Wannier functions are reported as well. Raman scattering from amorphous zones in neutron irradiated silicon. MEERA CHANDRASEKHAR, H. R. CHANDRASEKHAR and J. M. MEESE. Solid St. Commun. 38, 1113 (1981). A Raman scattering study of neutron irradiated silicon is presented for the first time. We have observed features in the Raman spectrum arising from amorphous zones produced in the bulk of the sample due to neutron induced defects. We relate these first order Raman modes to the crystalline vibrational density of states averaged over the Brillouin zone. The influence of mobile ions on the Si/SiO 2 interface traps. M. W. HtLLENand D. G. HEMMES.Solid-St. Electron. 24 (8) 773 (1981). An investigation of the relation between mobile ions and interface traps was carried out, using an appropriate technique to determine the number and type of mobile ions. it was found that mobile ions do not cause interface traps in the middle 0.8eV of the bandgap. It appears that interface traps are rather caused by some stress effect. The results are considered in light of previously reported work. 8. T H I C K -
AND THIN-FILM
COMPONENTS,
Britain takes the lead on hybrid components. Electronic Production p. 5 (August 1981 ). For the moment, Britain takes the lead since no other European country has an approval scheme for hybrid components for high reliability circuits. The new BS9000 scheme for "'assessors of add-on components" was necessary because hybrid microcircuits frequently use high technology hybrid components (often manufactured only off-shore) which need to be qualified within the BS9000 scheme if the hybrids are used in high reliability of military projects.
Polymer-monomer conversion in anthracene thin films as a switching and memory device. C. CHIANG. Solid St. Commun. 39, II1 (1981). The switching and memory phenomenon in anthracene thin films is explained by assuming the polymerization of anthracene molecules to a graphite-like polymer. When the voltage is a threshold point, the energetic electron and the secondary ionization may initiate the process similar to the polymerization. Since the polymer-like entity has graphite-like structure, it has higher conductivity, thus the film is switched to ON state. Since the molecule in a 9. E L E C T R O N ,
ION AND
Quenched-in-deep levels in boron-doped silicon. D. E. IOANNOU. Solid St. Commun. 39, 93 (1981). The DLTS technique was used to study quenched-in deep traps in boron doped silicon crystals, heated at temperatures in the range 700-900°C prior to quenching. The results vary with temperature, demonstrating that the exact temperature up to which the samples are heated prior to quenching plays a determining role on the number of different traps introduced and their positions in the energy gap, which is often overlooked in the literature. Analytical approach to hot electron transport in small size Mosfet's. J. P. LEBURTON,H. GESCH and G. DORDA. Solid-St. Electron. 24 (8) 763 (1981). A one-dimensional analytical description of the current transport in MOS transistors with a channel length of the order of I pm is presented. The theory is based on the empirical Scharfetter and Gummel formula expressing the velocity-field relation of the charge carriers in the Si bulk. A new formula is derived taking into account the surface condition. The analysis of the hot electron behavior in Si-inversion layers suggests the formulation of a new criterion for the failure of the usual "'gradual channel approximation", replacing the classical "'pinch-off" concept by a field relation factor f = Ey/Ex. I - U characteristics for different transistor channel lengths are calculated and compared with experimental data and with two-dimensional analyses. The agreement between both these results and our formulation is quite good and proves the accuracy of the one-dimensional approach. Cyclotron resonance at Na ÷-doped Si-Si02 interfaces. H. R. CHANG and F. KOCH. Solid St. Commun. 38, 1189 11981 ). We examine the cyclotron resonance of Si(100) surface electrons at interfaces with deliberate and controlled Na ÷ concentrations. At densities below 10tJNa ÷cm--" an unexpectedly strong damping and subsequent recovery of the resonance is found. For high Na + concentrations we confirm the scattering rate found from mobility studies, but disagree considerably with the SdH results. HYBRID
AND
MATERIALS
thin film cannot rotate as freely as in liquid, the polymer-like entity formed is under great bond strain, thus it may readily switch back to monomer anthracene molecule. However, if with repeated cycles, the polymer is at a relatively stable configuration with less bond strain, then it is in the memory state. Many experimental data of Elsharkawi and Kao may be explained with this model. Electro-optical properties of doped anthracene films. N. P. SINHA, Y. MISRA, L. N. TRIPATm and M. MISRA. Solid St. Cornmun. 39, 89 (.1981). Electroluminescence in anthracene doped with anthraquinone (10-~mole°o) films are presented. Films are deposited at room temperature in a vacuum of 10-Storr. It is observed that at constant frequency the brightness/voltage relationship follows the relation B = B o e x p ( - b / V I 2). The results show that electroluminescent brightness increases linearly with frequency. At lower frequencies green electroluminescent (EL) emission and at higher frequencies blue El_ emission is observed. Similar nature for l - V and brightness/voltage relationship are found in anthracene doped with 10 -4 mole o~, anthraquinone.
LASER
E-beam machines paired with optics pare wafer costs. J. ROBERT LINEBACK.Electronics p. 37 (16 June 1981 ). Electron beams scribe layers with fine-featured motifs; photolithography takes care of less-demanding layers.
CIRCUITS
BEAM
TECHNIQUES
Low-resistance, long-life contacts by laser-annealing of silverimplanted p-type PbTe. F. J. BRYANT and D. M. STAUDTE. Solid-St. Electron. 24, 675 (1981). Various procedures have been investigated for fabricating to p-type PbTe metal
World Abstracts on Microelectronics and Reliability
GalnAs and GalnAsP materials on lnP substrates have been developed. These two expitaxial growth techniques in the vapor phase, namely the hydrides method with multichamber reactor and the organometallics method at low pressure, make it possible to obtain high-quality materials for microwave and optronic applications. Diamond structure versus Wurtzite structure for silicon. J. SANCHEZ-DEHESA, J. A. VERGES and C. TEIEDOR. Solid St. Comraun. 38, 871 (1981). A calculation of the total energy of silicon in crystal structures with tetrahedral coordination is self-consistently performed in a Iocalised scheme. The behaviour of the total energy is similar to the one obtained with a rather sophisticated pseudopotential within a very different computational framework. We show that the change in the electrostatic energy is dominant over the remainder contributions, which makes it responsible for the stability of diamond with respect to wurtzite structure. Both the band structure and the interaction between Wannier functions are reported as well. Raman scattering from amorphous zones in neutron irradiated silicon. MEERA CHANDRASEKHAR, H. R. CHANDRASEKHAR and J. M. MEESE. Solid St. Commun. 38, 1113 (1981). A Raman scattering study of neutron irradiated silicon is presented for the first time. We have observed features in the Raman spectrum arising from amorphous zones produced in the bulk of the sample due to neutron induced defects. We relate these first order Raman modes to the crystalline vibrational density of states averaged over the Brillouin zone. The influence of mobile ions on the Si/SiO 2 interface traps. M. W. HtLLENand D. G. HEMMES.Solid-St. Electron. 24 (8) 773 (1981). An investigation of the relation between mobile ions and interface traps was carried out, using an appropriate technique to determine the number and type of mobile ions. it was found that mobile ions do not cause interface traps in the middle 0.8eV of the bandgap. It appears that interface traps are rather caused by some stress effect. The results are considered in light of previously reported work. 8. T H I C K -
AND THIN-FILM
COMPONENTS,
Britain takes the lead on hybrid components. Electronic Production p. 5 (August 1981 ). For the moment, Britain takes the lead since no other European country has an approval scheme for hybrid components for high reliability circuits. The new BS9000 scheme for "'assessors of add-on components" was necessary because hybrid microcircuits frequently use high technology hybrid components (often manufactured only off-shore) which need to be qualified within the BS9000 scheme if the hybrids are used in high reliability of military projects.
Polymer-monomer conversion in anthracene thin films as a switching and memory device. C. CHIANG. Solid St. Commun. 39, II1 (1981). The switching and memory phenomenon in anthracene thin films is explained by assuming the polymerization of anthracene molecules to a graphite-like polymer. When the voltage is a threshold point, the energetic electron and the secondary ionization may initiate the process similar to the polymerization. Since the polymer-like entity has graphite-like structure, it has higher conductivity, thus the film is switched to ON state. Since the molecule in a 9. E L E C T R O N ,
ION AND
Quenched-in-deep levels in boron-doped silicon. D. E. IOANNOU. Solid St. Commun. 39, 93 (1981). The DLTS technique was used to study quenched-in deep traps in boron doped silicon crystals, heated at temperatures in the range 700-900°C prior to quenching. The results vary with temperature, demonstrating that the exact temperature up to which the samples are heated prior to quenching plays a determining role on the number of different traps introduced and their positions in the energy gap, which is often overlooked in the literature. Analytical approach to hot electron transport in small size Mosfet's. J. P. LEBURTON,H. GESCH and G. DORDA. Solid-St. Electron. 24 (8) 763 (1981). A one-dimensional analytical description of the current transport in MOS transistors with a channel length of the order of I pm is presented. The theory is based on the empirical Scharfetter and Gummel formula expressing the velocity-field relation of the charge carriers in the Si bulk. A new formula is derived taking into account the surface condition. The analysis of the hot electron behavior in Si-inversion layers suggests the formulation of a new criterion for the failure of the usual "'gradual channel approximation", replacing the classical "'pinch-off" concept by a field relation factor f = Ey/Ex. I - U characteristics for different transistor channel lengths are calculated and compared with experimental data and with two-dimensional analyses. The agreement between both these results and our formulation is quite good and proves the accuracy of the one-dimensional approach. Cyclotron resonance at Na ÷-doped Si-Si02 interfaces. H. R. CHANG and F. KOCH. Solid St. Commun. 38, 1189 11981 ). We examine the cyclotron resonance of Si(100) surface electrons at interfaces with deliberate and controlled Na ÷ concentrations. At densities below 10tJNa ÷cm--" an unexpectedly strong damping and subsequent recovery of the resonance is found. For high Na + concentrations we confirm the scattering rate found from mobility studies, but disagree considerably with the SdH results. HYBRID
AND
MATERIALS
thin film cannot rotate as freely as in liquid, the polymer-like entity formed is under great bond strain, thus it may readily switch back to monomer anthracene molecule. However, if with repeated cycles, the polymer is at a relatively stable configuration with less bond strain, then it is in the memory state. Many experimental data of Elsharkawi and Kao may be explained with this model. Electro-optical properties of doped anthracene films. N. P. SINHA, Y. MISRA, L. N. TRIPATm and M. MISRA. Solid St. Cornmun. 39, 89 (.1981). Electroluminescence in anthracene doped with anthraquinone (10-~mole°o) films are presented. Films are deposited at room temperature in a vacuum of 10-Storr. It is observed that at constant frequency the brightness/voltage relationship follows the relation B = B o e x p ( - b / V I 2). The results show that electroluminescent brightness increases linearly with frequency. At lower frequencies green electroluminescent (EL) emission and at higher frequencies blue El_ emission is observed. Similar nature for l - V and brightness/voltage relationship are found in anthracene doped with 10 -4 mole o~, anthraquinone.
LASER
E-beam machines paired with optics pare wafer costs. J. ROBERT LINEBACK.Electronics p. 37 (16 June 1981 ). Electron beams scribe layers with fine-featured motifs; photolithography takes care of less-demanding layers.
CIRCUITS
BEAM
TECHNIQUES
Low-resistance, long-life contacts by laser-annealing of silverimplanted p-type PbTe. F. J. BRYANT and D. M. STAUDTE. Solid-St. Electron. 24, 675 (1981). Various procedures have been investigated for fabricating to p-type PbTe metal