Spin dependent trapping at a silicon grain boundary

World Abstracts on Microelectronics and Reliability that asperities can be approximated by spherical surfaces, and the breakdown voltage was then calculated at such asperities. Calculations showed that the breakdown voltage of a planar silicon dioxide capacitor can be lowered by one half to two thirds by asperities, when their radius is less than about one half of the oxide thickness. Such as decrease in the breakdown voltage is widely observed in polysilicon oxide capacitors. The effect of asperities is alleviated by a trapped electron charge, which can increase the breakdown voltage significantly. The spherical asperity model accounted for the breakdown voltages observed on a wide range of polysilicon oxide capacitors with oxide thicknesses varying from 45 to 820nm. The radius of asperities responsible for breakdown in these experiments was roughly estimated 25 35 nm.

Properties of metal semiconductor eontacts--I. Voltagecurrent characteristics of contacts on intrinsic semiconductors, J.-C. MANIFACIER,Y. MOREAU and H. K. HENISCH. Solid St. Electron. 26 (8) 795 (1983). In the general case (two carriers, arbitrary lifetime, arbitrary dielectric relaxation time), the transport equations relating to barrier characteristics have to be solved by numerical methods. The single-carrier case is already (abundantly) familiar, but the two-carrier case can also be solved explicitly. However, the solution is at all simple only for contacts on high lifetime intrinsic material. Such a solution is here obtained by conventional analytic methods, based on the diffusion theory and reasonable approximations, and is compared with computed results obtained on the complete (unapproximated) system. Analysis and computation lead to new and hitherto unrecognized dependence of the current on the applied voltage across the barrier in accordance with exp [2ql/~/kT], instead of the more familiar exp[qFo/kT]. The computational aspects as such receive detailed attention in Part II. The conclusions have important implications for the interpretation of non-ideality factors. The intrinsic case here treated reflects general modes of behavior; more specific results for extrinsic systems will be presented in Part III.

Amorphous silicon prepared by thermal decomposition of silane: properties and applications. R. BISARO, E. CHART1ER, D. KAPLAN,J. MAGAR1NO,N. PROUST and N. SZYDLO. Rev. Tech. Thomson-CSF 15 (2) 321 (June 1983) (In French). The authors present the properties of post-hydrogenated amorphous silicon prepared by chemical vapor deposition from silane. The structural properties have been studied by X-rays and Raman scattering to establish the crystallization conditions. The effects of post-hydrogenation and doping on the electrical properties are analysed. Simple devices such as Schottky and p-i-n diodes have been fabricated by this method. The applications to photovoltaics, high-power switching and non-linear I-V devices will be discussed. Epitaxial growth of GaAs in chloride transport systems. M. HEYEN and P. BALK. Prog. Crystal Growth Charact. 6, 265 (1983). In this paper, the thermodynamics and kinetics of GaAs growth in halide transport systems are reviewed. The problems related to the incorporation of impurities, both the intentional doping to obtain a desired donor or Receptor level and the problem of background doping are discussed, It is shown that our understanding of the growth process has reached a satisfactory level; in contrast, the mechanism of dopant incorporation still requires further study. Further sections are concerned with the electrical and optoelectronic properties of vapor grown GaAs. Finally, some practical and instrumental consequences of these insights for the growth of thin GaAs films are presented,

Advances in silicon technology for the semiconductor industry. Part II. ROBERT B. SWAROOP. Solid St. Technol. 97 (July 1983). Part I of this paper was published in our June '83 issue and reviewed the advances in silicon crystal growing and the effects of oxygen and carbon in the crystal. Part II describes

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the gettering methods for unwanted impurities in silicon wafers and reviews the silicon requirements for various circuit technologies.

Tight binding study of the silicon self-interstitial in tetrahedral site. P. PECHEURand G. TOUSSA~NT.Solid St. Commun. 47 (6) 507 (1983). The electronic structure of the silicon self-interstitial in tetrahedral site has been investigated with the Green function method using a tight binding Hamiltonian. The results are similar to those obtained within the local density formalism, provided that charge self consistency is included in the tight binding calculation. Precipitation process design for denuded zone formation in CZ-silieon wafers. DIETHARD HUBER and JOSEPH REFFLE. Solid St. Technol. 137 (August 1983). Modern microprocessor controlled silicon growth techniques can provide silicon materials with different tightly controlled oxygen ranges. For internal gettering purposes the precipitation rate of the interstitial oxygen is a parameter as important as the oxygen concentration itself. Fast precipitation rates, either grown into the material or generated by a low temperature preanneal can cause wafer warpage or may create a denuded zone not deep enough at the end of the device process. Materials which do not precipitate at normal process temperatures will obviously not generate internal gettering, but these materials allow the decoupling of the out-diffusion of oxygen from its precipitation. Thus, denuded zones and oxygen precipitates can be formed independently. Spin dependent trapping at a silicon grain boundary. P. M. LENAHANand W. K. SCHUBERT.Solid St. Commun. 47 (6) 423 (1983). We have observed, for the first time, spin dependent trapping in a silicon grain boundary. The results are quantitatively explained in terms of paramagnetic "dangling bond" interface traps and a majority carrier thermionic emission model. This is a sensitive and informative probe of defects in grain boundaries.

Hyperfine interactions from EPR of iron in silicon. E. G. SIEVERTS,S. H. MULLER, C. A. J. AMMERLAAN and E. R. WEBER.Solid St. Commun. 47 (8) 631 (1983). At high microwave power very well resolved EPR spectra from isolated neutral intersitial iron atoms in silicon can be observed. From these spectra hyperfine interactions with at least three shells of neighbouring lattice sites, containing 18 or 22 atoms, can be determined. The localization of the unpaired electron on these sites is only small. On nearest neighbour sites it is found to be even smaller than on next nearest sites. Investigation of the initial stages of oxidation of microcrystalline silicon by means of X-ray photoelectron spectroscopy. J. K. GIMZEWSK1and S. VEPREK.Solid St. Commun. 47 (9) 747 (1983). XPS Si2p spectra of microcrystalline silicon (lac-Si), prepared by plasma chemical transport are reported and the initial stages of oxidation are studied : In comparison with single crystal Si(111 ) surface, ~tc-Si samples are remarkably resistant to surface oxidation. A short exposure to air results in negligible oxygen adsorption (intensity ratio of 01s to Si2p peaks is less than 0.018 after more than 3 × 101~ Langmuirs exposure to air). Intensive oxidation treatment is required to produce an oxide layer and evidence supporting a preferential grain boundary oxidation mechanism is presented. The surface plasmon structure observed in the Si2p spectrum provides complementary information on the remarkably low oxidation rate of the crystallite surfaces as compared to the grain boundaries. Paramagnetic states in doped amorphous silicon and germanium. M. STUTZMANNand J. STUKE.Solid St. Commun. 47 (8) 635 (1983). ESR-results for doped hydrogenated amorphous silicon and germanium are discussed. ~q-values