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Far infrared resonant magnetoabsorption in low density Si inversion layers
260
World Abstracts on Microelectronics and Reliability
III V semiconductors is theoretically studied in the framework of the previously d e r i v e d [ l ] intermediate field theory. The new effect concerning the energetic differences of the a components in Faraday- and Voigt-configuration (firstly observed by Hess et al. [2]) is tightly connected with the LT-splitting constant A H and also with the field dependence of the oscillator strength of the Zeeman-doublet. The strong Voigt-components in GaAs should be (at 12 T) some tenths of a MeV higher in energy than their Faraday-counterparts. The weak components should show the effect in the order of magnitude of the experimental accuracy of measurement (~0.05 MeV at 12 T).
Spin-dependent photocondnctivity in n-type and p-type amorphous silicon. I. SOLOMON.Solid St. Commun. 22, 505 (1977). It is found that, as in crystalline silicon, the photoconductivity in amorphous silicon prepared by glow discharge is strongly spin-dependent. In this material, the position of the Fermi level can be smoothly varied by phosphorous or boron doping and the magnitude of the spin-dependent recombination has been measured as a function of the doping: it is found to have a large maximum when the material is intrinsic. The similarities with the spin-dependent effects in crystalline and dislocation silicon suggest that the recombination process in amorphous silicon is the same as in the crystalline material and that dislocation-like centres are responsible for the spin-dependent recombination properties in both materials.
Far infrared resonant magnetoabsorption in low density Si inversion layers. T. A. KENNEDY, R. J. WAGNER and B. D. McCOMBE, Solid St. Commun. 21, 459 (1977). The density and temperature dependences of high frequency/resonant field (61.3cm 1 11 T) resonant magnetoabsorption data in (100) Si inversion layers at low densities are strikingly different from those observed at lower frequencies/fields. The results, which include a dramatic resonant line narrowing at high fields, are discussed in light of single-electron localization and the possibility of a cooperative electronic transition assisted by the large magnetic field.
The effect of oxygen on the electrical properties of silicon. T. S. GLOWINKE and J. BRUCE WAGNER, JR. J. Phys. Chem. Solids 38, 963 (1977). Interstitial oxygen present in solution, as detected by the 9 # absorption band, increases the Hall mobility of electrons in n-type silicon crystals but decreases the Hall mobility of holes in p-types. These results are explained by the lattice strain produced via dissolved interstitial oxygen impurities. Results on samples saturated with oxygen a n d heat treated to cause precipitation of SiO2 in the temperature range of 950-1250°C show that the SiO2 particles decrease the values of Hall mobility compared to the initial values on samples without precipitates. Re-annealing causes the dissolution of the precipitates and recovery nearly to the initial values of the Hall coefficient.
Finally, the copper sulfide material is also presented as an example of polycristalline thin films.
Silicon for solar cells. J. J. BRISSOT. Acta Electron. 20, (2) 101 (1977). After a definition of requisites for an inexpensive industrialization of silicon solar cells for terrestrial applications, the different methods of elaboration of the silicon element are chronologically described as well as those of a solar grade material. It is shown that the fabrication of low cost cells require the study of new growth processes. In this prospect the main methods so far are successively reviewed in the field of single crystal ribbons and polycrystalline layers.
Fabrication and electrical properties of epitaxial layers of GaAs doped with manganese. L. GOUSKOV, S. BILAC, J. PXMENTEL and A. GOUSKOV. Solid-St. Electron. 20, 653 (1977). The method of fabrication of epitaxial layers of GaAs doped with Mn is described. Resistivity and Hall effect measurements are made on various samples in the temperature range 77-300°K. The experimental results are used to determine the densities N,, No of accetStors and compensating donors, the activation energy E, of the acceptor level associated with Mn and also the mobility of the carriers. These values are calculated using a model involving the two valence bands carriers. The results obtained confirm that the acceptor doping present a saturation. They are compared to results previously published. A new value, rather close to unity, is obtained for the distribution coefficient of Mn in the case of low doping.
Contactless nondestructive technique for the measurement of minority-carrier lifetime and diffusion length in silicon. J. C, WHITE, T. F. UNTER and J. G. SMITH. Solid St. eh'ctron. Devices 1 (5) 139 (Sept. 1977). A nondestructive contactless technique which allows high-resolution point-bypoint measurement of minority carrier lifetime and diffusion length in silicon, without the need for special structures, is described. Excess carriers are generated at a known rate by a 1 mW H e - N e laser beam focused to a fine spot on the silicon surface. The resulting total carrier number, which is inversely proportional to the recombination time, is detected by a novel infra-red emission technique. Spatial variations of lifetime have been measued, and small regions of high recombination located. Many of these can be associated with oxidation-induced stacking faults. The diffusion length is measured directly by observing the variation of carrier concentration with distance away from the point of injection. The technique is applicable to other semiconductors, and will be particularly valuable where it is difficult to make electrical contact.
Theoretical effects of surface diffused region lifetime models Structures for photocells: homojunctions, heterostructures or heterojunctions. E. FABRE. Acta Electron. 20, (2) 117 (1977). This paper deals with a comparative analysis of the different possible structures for the solar cells, and it is shown that the determination of the best structure mostly depends upon the physical characteristics of the base material, and especially its band structure. The three main types of collecting junctions (homojunction N-P, Schottky or MIS barrier, heterojunction) are analysed in the two particular cases of an indirect band gap semiconductor (silicon) and a direct band gap semiconductor (gallium arsenide).
on silicon solar cells. P. M. DUNBAR and J. g. HAUSER. Solid-St. Electron. 20, 697 (1977). A computer simulation
of silicon solar cells has indicated that the combination of band gap reduction due to heavy doping and certain spatial forms of lifetime dependence can combine to form severe limitations to the open circuit voltage of silicon solar cells. The interaction of these effects tends to shift the active region of the diffused surface layer away from the injecting junction resulting in an increase in the current density injected into the surface region. Reductions in open circuit voltage as great as 10% over models which do not include these effects can be seen.
World Abstracts on Microelectronics and Reliability
III V semiconductors is theoretically studied in the framework of the previously d e r i v e d [ l ] intermediate field theory. The new effect concerning the energetic differences of the a components in Faraday- and Voigt-configuration (firstly observed by Hess et al. [2]) is tightly connected with the LT-splitting constant A H and also with the field dependence of the oscillator strength of the Zeeman-doublet. The strong Voigt-components in GaAs should be (at 12 T) some tenths of a MeV higher in energy than their Faraday-counterparts. The weak components should show the effect in the order of magnitude of the experimental accuracy of measurement (~0.05 MeV at 12 T).
Spin-dependent photocondnctivity in n-type and p-type amorphous silicon. I. SOLOMON.Solid St. Commun. 22, 505 (1977). It is found that, as in crystalline silicon, the photoconductivity in amorphous silicon prepared by glow discharge is strongly spin-dependent. In this material, the position of the Fermi level can be smoothly varied by phosphorous or boron doping and the magnitude of the spin-dependent recombination has been measured as a function of the doping: it is found to have a large maximum when the material is intrinsic. The similarities with the spin-dependent effects in crystalline and dislocation silicon suggest that the recombination process in amorphous silicon is the same as in the crystalline material and that dislocation-like centres are responsible for the spin-dependent recombination properties in both materials.
Far infrared resonant magnetoabsorption in low density Si inversion layers. T. A. KENNEDY, R. J. WAGNER and B. D. McCOMBE, Solid St. Commun. 21, 459 (1977). The density and temperature dependences of high frequency/resonant field (61.3cm 1 11 T) resonant magnetoabsorption data in (100) Si inversion layers at low densities are strikingly different from those observed at lower frequencies/fields. The results, which include a dramatic resonant line narrowing at high fields, are discussed in light of single-electron localization and the possibility of a cooperative electronic transition assisted by the large magnetic field.
The effect of oxygen on the electrical properties of silicon. T. S. GLOWINKE and J. BRUCE WAGNER, JR. J. Phys. Chem. Solids 38, 963 (1977). Interstitial oxygen present in solution, as detected by the 9 # absorption band, increases the Hall mobility of electrons in n-type silicon crystals but decreases the Hall mobility of holes in p-types. These results are explained by the lattice strain produced via dissolved interstitial oxygen impurities. Results on samples saturated with oxygen a n d heat treated to cause precipitation of SiO2 in the temperature range of 950-1250°C show that the SiO2 particles decrease the values of Hall mobility compared to the initial values on samples without precipitates. Re-annealing causes the dissolution of the precipitates and recovery nearly to the initial values of the Hall coefficient.
Finally, the copper sulfide material is also presented as an example of polycristalline thin films.
Silicon for solar cells. J. J. BRISSOT. Acta Electron. 20, (2) 101 (1977). After a definition of requisites for an inexpensive industrialization of silicon solar cells for terrestrial applications, the different methods of elaboration of the silicon element are chronologically described as well as those of a solar grade material. It is shown that the fabrication of low cost cells require the study of new growth processes. In this prospect the main methods so far are successively reviewed in the field of single crystal ribbons and polycrystalline layers.
Fabrication and electrical properties of epitaxial layers of GaAs doped with manganese. L. GOUSKOV, S. BILAC, J. PXMENTEL and A. GOUSKOV. Solid-St. Electron. 20, 653 (1977). The method of fabrication of epitaxial layers of GaAs doped with Mn is described. Resistivity and Hall effect measurements are made on various samples in the temperature range 77-300°K. The experimental results are used to determine the densities N,, No of accetStors and compensating donors, the activation energy E, of the acceptor level associated with Mn and also the mobility of the carriers. These values are calculated using a model involving the two valence bands carriers. The results obtained confirm that the acceptor doping present a saturation. They are compared to results previously published. A new value, rather close to unity, is obtained for the distribution coefficient of Mn in the case of low doping.
Contactless nondestructive technique for the measurement of minority-carrier lifetime and diffusion length in silicon. J. C, WHITE, T. F. UNTER and J. G. SMITH. Solid St. eh'ctron. Devices 1 (5) 139 (Sept. 1977). A nondestructive contactless technique which allows high-resolution point-bypoint measurement of minority carrier lifetime and diffusion length in silicon, without the need for special structures, is described. Excess carriers are generated at a known rate by a 1 mW H e - N e laser beam focused to a fine spot on the silicon surface. The resulting total carrier number, which is inversely proportional to the recombination time, is detected by a novel infra-red emission technique. Spatial variations of lifetime have been measued, and small regions of high recombination located. Many of these can be associated with oxidation-induced stacking faults. The diffusion length is measured directly by observing the variation of carrier concentration with distance away from the point of injection. The technique is applicable to other semiconductors, and will be particularly valuable where it is difficult to make electrical contact.
Theoretical effects of surface diffused region lifetime models Structures for photocells: homojunctions, heterostructures or heterojunctions. E. FABRE. Acta Electron. 20, (2) 117 (1977). This paper deals with a comparative analysis of the different possible structures for the solar cells, and it is shown that the determination of the best structure mostly depends upon the physical characteristics of the base material, and especially its band structure. The three main types of collecting junctions (homojunction N-P, Schottky or MIS barrier, heterojunction) are analysed in the two particular cases of an indirect band gap semiconductor (silicon) and a direct band gap semiconductor (gallium arsenide).
on silicon solar cells. P. M. DUNBAR and J. g. HAUSER. Solid-St. Electron. 20, 697 (1977). A computer simulation
of silicon solar cells has indicated that the combination of band gap reduction due to heavy doping and certain spatial forms of lifetime dependence can combine to form severe limitations to the open circuit voltage of silicon solar cells. The interaction of these effects tends to shift the active region of the diffused surface layer away from the injecting junction resulting in an increase in the current density injected into the surface region. Reductions in open circuit voltage as great as 10% over models which do not include these effects can be seen.