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Raman scattering from gas-evaporated silicon small particles
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World Abstracts on Microelectronics and Reliabilit 3 7. S E M I C O N D U C T O R
INTEGRATED
A gaseous detector device for an environmental SEM. G. D. DAN1LATOS.Micron Microscopica Acta. 14 (4), 307 (1983). A new detection system has been used in the environmental SEM. The presence of gaseous and liquid phases in the microscope has made possible the formation of images of both insulators and conductors using the current mode. In addition, the ionizing radiations create in the gas negative and positive charge carriers which contain information from the beam specimen interaction. These carriers, when collected by suitable means, such as a biased wire away from the specimen, can modulate the display signal to form images. Thus, the gas itself constitutes the basic component of a signal detector device, apart from its use as a conditioning medium.
Carrier mobility in inversion layers and rf plasma induced radiation defects at the Si-SiO 2 interface. J. KASSABOV, E. ATANASSOVAand E. GORANOVA.Solid-St. Electron. 27(1), 13 (1984). Radiation defects in the Si SiO2 system caused by plasma etching or oxidation (d = 35 A) as well as rf 0 2 plasma treatment of the thermal oxide (d = 50 A and d = 1000 A) are investigated by making use of steady-state conductance measurements of inversion layers. It is found that the defects act as trapping centers leading to a rapid decrease of the channel conductivity at room temperature. The presence of positive charge in the ultrathin plasma oxide and an additional built-in negative charge in an oxygen plasma treated thermal oxide is observed. Conclusions on scattering processes are made from the temperature dependence of carrier mobility.
Current transport mechanisms of electrochemically deposited CdS/CdTe heterojunction. S. S. Ou, O. M. STAFSUDD and B. M. BASOL. Solid-St. Electron. 27 (1), 21 (1984). The dark current transport mechanism in electrochemically deposited n-CdS/p-CdTe thin film heterojunctions is investigated. The forward current measured in the temperature range between 200 ° and 305°K can be expressed as Jf = J0(T)exp (AV) and the reverse current can be expressed as J, = - C V e x p - C V [ - 2 ( V d - V) tl/2)]. The current mechanisms are consistent with a multi step recombination-tunneling model.
On speeding-up of iteration convergence in semiconductor problems. B. S. POLSKY. Solid-St. Electron. 27 (2), 191 (1984). An iterative method for solving steady-state semiconductor problems is proposed. The method is based on an alternate solution of the linearized Poisson equation and the continuity equations. The presented numerical results show that the convergence rate of the method at high injection conditions is essentially greater than that of the traditional G u m m e l algorithm.
Theory of the surface depletion region for semiconductors with linearly graded impurity profiles. S. W. TARASEWICZ and C. A. T. SALAMA.Solid-St. Electron. 27 (1), 33 (1984). The theory of the surface depletion region for a semiconductor with a linearly graded impurity profile is described in this paper. Using the depletion approximation, expressions for the electric field, potential and surface potential are derived as functions of the profile parameters. The theoretical high frequency CV characteristics of an MOS structure built on such a surface are generated and compared with the experimental results obtained on M O S capacitors fabricated on implanted surfaces. The agreement between the theory and experimental results is very good. Since m a n y diffused and implanted profiles can be approximated by piecewise-linear segments, the theory presented here can be extended and
CIRCUITS,
DEVICES
AND
MATERIALS
used in the modelling and simulation of a variety of ionimplanted M O S structures.
Diffusion length and surface recombination velocity measurements with the scanning electron microscope: the highly-doped emitter of a p-n junction. D. E. BURK and R. SUNDARESAN. Solid-St. Electron. 27 (1), 59 (1984). Analytical solutions of the electron-beam induced current response for a spherical source excitation are formulated for a finite region of semiconductor using the method of images. The analytic approach is different from that normally reported for semi-infinite region analysis because it incorporates a third boundary condition into the problem. Consequently, it is more general because it is valid for all regions of width greater than or equal to two real excitation volume radii. The analytic solutions predict that absolute, not relative, current responses must be used to determine diffusion lengths in finite regions of semiconductors and that the slope of the response is relatively insensitive to the surface recombination velocities. The solutions are demonstrated to correctly fit normalized data for the response of a highly-doped emitter.
Computer analysis on the collection of alpha-generated charge for reflecting and absorbing surface conditions around the collector. K. TERRILL, C. H u and A. NEUREUTHER. Solid-St. Electron. 27 (1), 45 (1984). We present an analysis of the collection of alpha-particle generated charge by collectors surrounded by either uniform reflecting or uniform absorbing surfaces. These are the two extreme cases of any real condition that exists in IC's. The analysis of the upper limit of charge collection should be more useful for circuit design than the previously available lower limit. It is assumed that the charge transport is by diffusion. The effects of collector size, or-particle energy, and the separation between the collector and the alpha track are studied. When the orparticle strike is through the center of the collector, the difference in collected charge for the two cases is up to a factor of two. When the or-particle strike does not pass through the collector, the difference is much greater. The collected charge scales approximately linearly with the collector side length.
Density of states modifications in amorphous and hydrogenated amorphous germanium and their effect on 3d core levels binding energy. F. PATELLA, F'. SETTE, P. PERFETTI, C. QUARESIMA, C. CAPASSO, M. CAPOZI, A. SAVOIA and F. EVANGELISTI. Solid St. Commun. 49 (8), 749 (1984). By using photoemission and partial yield spectroscopies the conduction band edge, the valence band and the 3d core levels of a m o r p h o u s germanium hydrogenated and nonhydrogenated are studied and compared to that of crystalline Ge. We measure a 0.25 eV shift of the 3d core levels of a m o r p h o u s Ge as compared to crystalline Ge whereas a smaller shift and a slight line--broadening are found in hydrogenated amorphous samples with low H content. These results are discussed in terms of the contribution to the self energy due to relaxation of the valence electrons when a core hole is created.
Raman scattering from gas-evaporated silicon small particles. T. OKADA,T. IWAKI, K. YAMAMOTO,H. KASAHARAand K. ABE. Solid St. Commun. 49 (8), 809 (1984). R a m a n scattering measurements are reported on silicon small particles prepared by gas-evaporation technique. The crystalline structure is also observed for the sample having 70A particles in average size. Four resolved component modes with Gaussian distribution function are identified with the three usual modes (LA, T O and allowed-TO) and a new surface mode. The surface mode of silicon particle, whose relative integrated intensity decrease with an increase of the particle size, is presented for the first time.
World Abstracts on Microelectronics and Reliabilit 3 7. S E M I C O N D U C T O R
INTEGRATED
A gaseous detector device for an environmental SEM. G. D. DAN1LATOS.Micron Microscopica Acta. 14 (4), 307 (1983). A new detection system has been used in the environmental SEM. The presence of gaseous and liquid phases in the microscope has made possible the formation of images of both insulators and conductors using the current mode. In addition, the ionizing radiations create in the gas negative and positive charge carriers which contain information from the beam specimen interaction. These carriers, when collected by suitable means, such as a biased wire away from the specimen, can modulate the display signal to form images. Thus, the gas itself constitutes the basic component of a signal detector device, apart from its use as a conditioning medium.
Carrier mobility in inversion layers and rf plasma induced radiation defects at the Si-SiO 2 interface. J. KASSABOV, E. ATANASSOVAand E. GORANOVA.Solid-St. Electron. 27(1), 13 (1984). Radiation defects in the Si SiO2 system caused by plasma etching or oxidation (d = 35 A) as well as rf 0 2 plasma treatment of the thermal oxide (d = 50 A and d = 1000 A) are investigated by making use of steady-state conductance measurements of inversion layers. It is found that the defects act as trapping centers leading to a rapid decrease of the channel conductivity at room temperature. The presence of positive charge in the ultrathin plasma oxide and an additional built-in negative charge in an oxygen plasma treated thermal oxide is observed. Conclusions on scattering processes are made from the temperature dependence of carrier mobility.
Current transport mechanisms of electrochemically deposited CdS/CdTe heterojunction. S. S. Ou, O. M. STAFSUDD and B. M. BASOL. Solid-St. Electron. 27 (1), 21 (1984). The dark current transport mechanism in electrochemically deposited n-CdS/p-CdTe thin film heterojunctions is investigated. The forward current measured in the temperature range between 200 ° and 305°K can be expressed as Jf = J0(T)exp (AV) and the reverse current can be expressed as J, = - C V e x p - C V [ - 2 ( V d - V) tl/2)]. The current mechanisms are consistent with a multi step recombination-tunneling model.
On speeding-up of iteration convergence in semiconductor problems. B. S. POLSKY. Solid-St. Electron. 27 (2), 191 (1984). An iterative method for solving steady-state semiconductor problems is proposed. The method is based on an alternate solution of the linearized Poisson equation and the continuity equations. The presented numerical results show that the convergence rate of the method at high injection conditions is essentially greater than that of the traditional G u m m e l algorithm.
Theory of the surface depletion region for semiconductors with linearly graded impurity profiles. S. W. TARASEWICZ and C. A. T. SALAMA.Solid-St. Electron. 27 (1), 33 (1984). The theory of the surface depletion region for a semiconductor with a linearly graded impurity profile is described in this paper. Using the depletion approximation, expressions for the electric field, potential and surface potential are derived as functions of the profile parameters. The theoretical high frequency CV characteristics of an MOS structure built on such a surface are generated and compared with the experimental results obtained on M O S capacitors fabricated on implanted surfaces. The agreement between the theory and experimental results is very good. Since m a n y diffused and implanted profiles can be approximated by piecewise-linear segments, the theory presented here can be extended and
CIRCUITS,
DEVICES
AND
MATERIALS
used in the modelling and simulation of a variety of ionimplanted M O S structures.
Diffusion length and surface recombination velocity measurements with the scanning electron microscope: the highly-doped emitter of a p-n junction. D. E. BURK and R. SUNDARESAN. Solid-St. Electron. 27 (1), 59 (1984). Analytical solutions of the electron-beam induced current response for a spherical source excitation are formulated for a finite region of semiconductor using the method of images. The analytic approach is different from that normally reported for semi-infinite region analysis because it incorporates a third boundary condition into the problem. Consequently, it is more general because it is valid for all regions of width greater than or equal to two real excitation volume radii. The analytic solutions predict that absolute, not relative, current responses must be used to determine diffusion lengths in finite regions of semiconductors and that the slope of the response is relatively insensitive to the surface recombination velocities. The solutions are demonstrated to correctly fit normalized data for the response of a highly-doped emitter.
Computer analysis on the collection of alpha-generated charge for reflecting and absorbing surface conditions around the collector. K. TERRILL, C. H u and A. NEUREUTHER. Solid-St. Electron. 27 (1), 45 (1984). We present an analysis of the collection of alpha-particle generated charge by collectors surrounded by either uniform reflecting or uniform absorbing surfaces. These are the two extreme cases of any real condition that exists in IC's. The analysis of the upper limit of charge collection should be more useful for circuit design than the previously available lower limit. It is assumed that the charge transport is by diffusion. The effects of collector size, or-particle energy, and the separation between the collector and the alpha track are studied. When the orparticle strike is through the center of the collector, the difference in collected charge for the two cases is up to a factor of two. When the or-particle strike does not pass through the collector, the difference is much greater. The collected charge scales approximately linearly with the collector side length.
Density of states modifications in amorphous and hydrogenated amorphous germanium and their effect on 3d core levels binding energy. F. PATELLA, F'. SETTE, P. PERFETTI, C. QUARESIMA, C. CAPASSO, M. CAPOZI, A. SAVOIA and F. EVANGELISTI. Solid St. Commun. 49 (8), 749 (1984). By using photoemission and partial yield spectroscopies the conduction band edge, the valence band and the 3d core levels of a m o r p h o u s germanium hydrogenated and nonhydrogenated are studied and compared to that of crystalline Ge. We measure a 0.25 eV shift of the 3d core levels of a m o r p h o u s Ge as compared to crystalline Ge whereas a smaller shift and a slight line--broadening are found in hydrogenated amorphous samples with low H content. These results are discussed in terms of the contribution to the self energy due to relaxation of the valence electrons when a core hole is created.
Raman scattering from gas-evaporated silicon small particles. T. OKADA,T. IWAKI, K. YAMAMOTO,H. KASAHARAand K. ABE. Solid St. Commun. 49 (8), 809 (1984). R a m a n scattering measurements are reported on silicon small particles prepared by gas-evaporation technique. The crystalline structure is also observed for the sample having 70A particles in average size. Four resolved component modes with Gaussian distribution function are identified with the three usual modes (LA, T O and allowed-TO) and a new surface mode. The surface mode of silicon particle, whose relative integrated intensity decrease with an increase of the particle size, is presented for the first time.