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Spontaneous emission by ballistic electronics in semiconducting heterostructures
830
World Abstracts on Microelectronics and Reliability
temperatures, have been measured. Photoluminescence at 2 K showed that these are the purest InP epilayers that have been reported in the literature. Ultrahigh voltage silicon P - N junctions with a breakdown voltage above 20 kV. E. V. ASTROVA,V. M. VOLLE, V. B. VORONKOV, I. V. GREKHOV, V. A. KOZLOV and A. A. LEDEDEV. Solid-St. Electron. 32(10), 851 (1989). Using Ntype silicon wafers (p ~ 1.7-2 kf~ cm, 40 mm diameter and 3.5 mm thickness) P - N junctions with a breakdown voltage exceeding 20 kV have been manufactured. Applying a combination of slow-heating, slow-cooling and using polished float-zone Si and phosphorous silicon oxide glass layers for gettering the thermal defects, it was possible to avoid a change in resistivity of the n-layer and to fabricate devices with an ideal blocking capability. Chemical potential shift in Si(100) MOS structure induced by submillimeter radiation. N. B. ZHITENEV.Solid-St. Commun. 71(5), 351 (1989). In Si-MOS structure on (100) surface in a normal quantizing magnetic field a change in the voltage between the gate and the 2d electron layer was found induced by electromagnetic irradiation with wavelength 2 ~< 1 ram. It is shown that the effect is due to the shift of the chemical potential of 2d electrons caused by the increase in temperature of the electron subsystem in contrast to the causes leading to an analogous effect in GaAs/A1GaAs heterojunction. Charge trapping and dielectric breakdown in MOS devices in 77--400 K temperature range. C.-L. HUANG, S. A. GROT, S. SH. GILDENBLAT and V. BOLKHOVSKY. Solid-St. Electron. 32(9), 767 (1989). We report the results of an experimental investigation of the temperature dependence of electron trapping and dielectric breakdown in MOS devices operated in the 77400 K temperature range. In contrast to avalanche or hot-electron injection investigated previously, the trapping of electrons in the regime of tunneling injection is suppressed at low temperatures. This result is related to the retardation of the time-dependent dielectric breakdown observed for the low-temperature operation of MOS devices. It is shown that both the failure rate and the temperature dependence of the time-dependent dielectric breakdown is reduced for the low-temperature operation. If the Arrhenius law is used to describe the maximum number of carriers which can be injected into SiO2 prior to dielectric breakdown, then for temperatures between 77 and 200 K the activation energy is reduced by approximately an order of magnitude as compared with its room-temperature value. Three-dimensional properties of conduction electronics in semiconductor superlattices. ]NTAOTERUSHIGEKAWA.Solid-St. Electron. 32(9), 761 (1989). The deviation of electron scattering probability in semiconductor superlattices from its bulk value is proposed as an index of 3-D properties of conduction electrons in semiconductor superlattices. The relative deviation of scattering probability is numerically calculated for acoustic-phonon scattering, ionized-impurity scattering, and polar-optical phonon scattering in GaAs/A1045Ga0.55As superlattices. By comparing the three scattering processes, it is found that the probability of acoustic-phonon scattering in the superlattices deviates to the largest extent, and that the difference in the relative deviations of the scattering probabilities is due to the wave-vector dependences of the respective scattering processes. Breakdown in SiO 2 films in VLSI MOS structures. J. StmE, I.PLACENCIA, E. FARRES, N. BARN1OL and X. AYMERICH. Vacuum 39(7/8), 765 (1989). A new model for the degradation and breakdown of thin SiO2 films is presented. The oxide degradation is due to the fact that part of the kinetic energy of the injected electrons is converted into the generation of defects that behave as electron traps. From the
experimental evolution of the stress conditions, the breakdown times are predicted as a function of the applied current in constant-current stress experiments. From the constantcurrent stress breakdown characteristics, the experimental I - V characteristic and the time-to-breakdown o f a MOS structure submitted to a voltage-ramp stress are also well predicted. Due to the generated negative charge density in the SiO 2 bulk, the energy barrier becomes parabolic. The I - V tunnelling characteristic through such a barrier has been studied in detail. On the oxide interface micro-roughness in MOS devices. I. PLACENC1A, J. SUNE, E. FARRES, N. BARNIOL and X. AYMERICH. Vacuum 39(7/8), 771 (1989). A new model for mathematically describing the thickness inhomogeneities of SiO 2 layers of MOS structures is presented. This model is compatible with the mechanisms of silicon oxidation and, hence, it can be used to study the influence of the oxidation conditions on the final roughness of the SiO 2 layer interfaces. The experimental SiOx interface transition layer has been re-interpreted in terms of the interface micro-roughness and, using the proposed thickness distribution function, the shape of this transition layer is obtained. The experimental thickness extent of this transition layer is well fitted in the presented model with a unity step of the order of the SiO 2 cell dimension ( ~ 7 A). Electronic structure of substitutional oxygen in silicon. I. ORTEGA-BLAKE, J. TAGUENA-MARTINEZ,R. A. BARRIO, E. MARTINEZand FELIXYNDURAIN.Solid-St. Commun. 71(12), l l07 (1989). The electronic distribution around substitutional oxygen in silicon is calculated. The equilibrium position of oxygen with respect to its neighbouring silicon atoms is obtained via a total energy minimization in finite clusters of atoms. Oxygen is found to be an off-center impurity deviating 0.90 A in the (100) direction from the nominal position of the silicon atom it replaces in agreement with previous models. The Si---O--Si bond formed is similar to that of SiO2 although the S i ~ distance is 1.82 A instead of 1.61 A. The two other silicon atoms in the vacancy approach each other, forming a new bond responsible for the experimentally found net acceptor character of the defect. Detection of ~t-particles via phonous by ionization of A + centers in silicon. TH. LANGE, E. UMLAUF and W. ZULEHNER. Solid-St. Commun. 71(8), 697 (1989). We show that phonon detection by phonon-induced currents in doped semiconductors can be used to detect single particles from radioactive sources. With 5.5 MeV or-particles an energy resolution of about 100 keV has been found on a large Si:B detector. Spontaneous emission by ballistic electronics in semiconducting heterostructures. M. BOTTO~ and A. RoN. Solid-St. Commun. 71(12), 1131 (1989). We investigate the spontaneous emission by electrons traversing ballistically a superlattice in semiconducting heterostructures. It is found that for an injected current of 100/~A into a 5 × 20#m 2 device there are about 5 x 108 s - ~infra-red photons emitted, mostly perpendicular to the electrons' direction of motion. We also estimate the gain of the structure, and find that stimulated emission occurs when the threshold current density is of order l04 A cm -2. Amorphous--crystalline silicon heterojuuction: theoretical evaluation of the current terms. F. Rum~mLLI, S. ALBORNOZ and R. BUITRAGO.Solid-St. Electron. 32(10), 813 (1989). In this paper, the current mechanisms and the theoretical performance as a solar cell of an amorphous-crystalline silicon heterojunction are evaluated and their dependence on the amorphous silicon doping level, the interface state density, the amorphous silicon density of gap states and the
World Abstracts on Microelectronics and Reliability
temperatures, have been measured. Photoluminescence at 2 K showed that these are the purest InP epilayers that have been reported in the literature. Ultrahigh voltage silicon P - N junctions with a breakdown voltage above 20 kV. E. V. ASTROVA,V. M. VOLLE, V. B. VORONKOV, I. V. GREKHOV, V. A. KOZLOV and A. A. LEDEDEV. Solid-St. Electron. 32(10), 851 (1989). Using Ntype silicon wafers (p ~ 1.7-2 kf~ cm, 40 mm diameter and 3.5 mm thickness) P - N junctions with a breakdown voltage exceeding 20 kV have been manufactured. Applying a combination of slow-heating, slow-cooling and using polished float-zone Si and phosphorous silicon oxide glass layers for gettering the thermal defects, it was possible to avoid a change in resistivity of the n-layer and to fabricate devices with an ideal blocking capability. Chemical potential shift in Si(100) MOS structure induced by submillimeter radiation. N. B. ZHITENEV.Solid-St. Commun. 71(5), 351 (1989). In Si-MOS structure on (100) surface in a normal quantizing magnetic field a change in the voltage between the gate and the 2d electron layer was found induced by electromagnetic irradiation with wavelength 2 ~< 1 ram. It is shown that the effect is due to the shift of the chemical potential of 2d electrons caused by the increase in temperature of the electron subsystem in contrast to the causes leading to an analogous effect in GaAs/A1GaAs heterojunction. Charge trapping and dielectric breakdown in MOS devices in 77--400 K temperature range. C.-L. HUANG, S. A. GROT, S. SH. GILDENBLAT and V. BOLKHOVSKY. Solid-St. Electron. 32(9), 767 (1989). We report the results of an experimental investigation of the temperature dependence of electron trapping and dielectric breakdown in MOS devices operated in the 77400 K temperature range. In contrast to avalanche or hot-electron injection investigated previously, the trapping of electrons in the regime of tunneling injection is suppressed at low temperatures. This result is related to the retardation of the time-dependent dielectric breakdown observed for the low-temperature operation of MOS devices. It is shown that both the failure rate and the temperature dependence of the time-dependent dielectric breakdown is reduced for the low-temperature operation. If the Arrhenius law is used to describe the maximum number of carriers which can be injected into SiO2 prior to dielectric breakdown, then for temperatures between 77 and 200 K the activation energy is reduced by approximately an order of magnitude as compared with its room-temperature value. Three-dimensional properties of conduction electronics in semiconductor superlattices. ]NTAOTERUSHIGEKAWA.Solid-St. Electron. 32(9), 761 (1989). The deviation of electron scattering probability in semiconductor superlattices from its bulk value is proposed as an index of 3-D properties of conduction electrons in semiconductor superlattices. The relative deviation of scattering probability is numerically calculated for acoustic-phonon scattering, ionized-impurity scattering, and polar-optical phonon scattering in GaAs/A1045Ga0.55As superlattices. By comparing the three scattering processes, it is found that the probability of acoustic-phonon scattering in the superlattices deviates to the largest extent, and that the difference in the relative deviations of the scattering probabilities is due to the wave-vector dependences of the respective scattering processes. Breakdown in SiO 2 films in VLSI MOS structures. J. StmE, I.PLACENCIA, E. FARRES, N. BARN1OL and X. AYMERICH. Vacuum 39(7/8), 765 (1989). A new model for the degradation and breakdown of thin SiO2 films is presented. The oxide degradation is due to the fact that part of the kinetic energy of the injected electrons is converted into the generation of defects that behave as electron traps. From the
experimental evolution of the stress conditions, the breakdown times are predicted as a function of the applied current in constant-current stress experiments. From the constantcurrent stress breakdown characteristics, the experimental I - V characteristic and the time-to-breakdown o f a MOS structure submitted to a voltage-ramp stress are also well predicted. Due to the generated negative charge density in the SiO 2 bulk, the energy barrier becomes parabolic. The I - V tunnelling characteristic through such a barrier has been studied in detail. On the oxide interface micro-roughness in MOS devices. I. PLACENC1A, J. SUNE, E. FARRES, N. BARNIOL and X. AYMERICH. Vacuum 39(7/8), 771 (1989). A new model for mathematically describing the thickness inhomogeneities of SiO 2 layers of MOS structures is presented. This model is compatible with the mechanisms of silicon oxidation and, hence, it can be used to study the influence of the oxidation conditions on the final roughness of the SiO 2 layer interfaces. The experimental SiOx interface transition layer has been re-interpreted in terms of the interface micro-roughness and, using the proposed thickness distribution function, the shape of this transition layer is obtained. The experimental thickness extent of this transition layer is well fitted in the presented model with a unity step of the order of the SiO 2 cell dimension ( ~ 7 A). Electronic structure of substitutional oxygen in silicon. I. ORTEGA-BLAKE, J. TAGUENA-MARTINEZ,R. A. BARRIO, E. MARTINEZand FELIXYNDURAIN.Solid-St. Commun. 71(12), l l07 (1989). The electronic distribution around substitutional oxygen in silicon is calculated. The equilibrium position of oxygen with respect to its neighbouring silicon atoms is obtained via a total energy minimization in finite clusters of atoms. Oxygen is found to be an off-center impurity deviating 0.90 A in the (100) direction from the nominal position of the silicon atom it replaces in agreement with previous models. The Si---O--Si bond formed is similar to that of SiO2 although the S i ~ distance is 1.82 A instead of 1.61 A. The two other silicon atoms in the vacancy approach each other, forming a new bond responsible for the experimentally found net acceptor character of the defect. Detection of ~t-particles via phonous by ionization of A + centers in silicon. TH. LANGE, E. UMLAUF and W. ZULEHNER. Solid-St. Commun. 71(8), 697 (1989). We show that phonon detection by phonon-induced currents in doped semiconductors can be used to detect single particles from radioactive sources. With 5.5 MeV or-particles an energy resolution of about 100 keV has been found on a large Si:B detector. Spontaneous emission by ballistic electronics in semiconducting heterostructures. M. BOTTO~ and A. RoN. Solid-St. Commun. 71(12), 1131 (1989). We investigate the spontaneous emission by electrons traversing ballistically a superlattice in semiconducting heterostructures. It is found that for an injected current of 100/~A into a 5 × 20#m 2 device there are about 5 x 108 s - ~infra-red photons emitted, mostly perpendicular to the electrons' direction of motion. We also estimate the gain of the structure, and find that stimulated emission occurs when the threshold current density is of order l04 A cm -2. Amorphous--crystalline silicon heterojuuction: theoretical evaluation of the current terms. F. Rum~mLLI, S. ALBORNOZ and R. BUITRAGO.Solid-St. Electron. 32(10), 813 (1989). In this paper, the current mechanisms and the theoretical performance as a solar cell of an amorphous-crystalline silicon heterojunction are evaluated and their dependence on the amorphous silicon doping level, the interface state density, the amorphous silicon density of gap states and the