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Refractory materials
A B S T R A C T S ON M I C R O E L E C T R O N I C S AND R E L I A B I L I T Y
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parasitic transistor unit along with a current generator to account for the effect of the substrate. Under some operating conditions, this model is simplified to include one diode and a current generator in addition to the transistor, and in other circumstances to require only a simple current generator along with the transistor itself. The measurements necessary for determining the parameters of the complete model are identified. The pertinent constants can be obtained from the terminal currents of the device under specified operating conditions.
An automatic test set for measuring dopant concentration profiles in epitaxial films. G. W. REUTLINGER,S. J. REGAS,D. J. SIDOR and B. SCHWARTZ,Solid-St. Electron. 12 (1969), p. 31. Dopant profiles in epitaxial films can be obtained by measuring the junction capacitance, the rate of change of capacitance with respect to applied voltage, and the area o f p - n diodes made in the films. A test set has been designed and constructed which automatically measures and records on IBM cards a series of voltages and corresponding capacitances of a diode made from the film to be evaluated. Optical means are provided in the test fixture for measuring the diode area. The test set is capable of measuring up to 100 C-V points at a rate of about 15 points per rain. The total measurement time for a typical diode, including diode area measurement, is less than 4 rain. Manual C-V measurement and card punching would take at least 30 min per diode. The punched cards are processed by an IBM 7094 computer and an SC 4020 microfilm plotter to obtain the dopant profile. The computation cost is about 18 cents per diode. System and component requirements are given and the computer program in Fortran II is included.
Depletion layer and capacitance calculations for gaussian diffused junctions. P. R. WILSON, Solid-St. Electron. 12 (1969), p. 1. Expressions are derived for the voltage dependence of the depletion layer width, the maximum electric field and the capacitance of Gaussian diffused plane, cylindrical and spherical p-n junctions. These are also shown in graphical form for junctions in silicon for a ratio of surface to background concentration covering the range 102-107 . It is shown that the junctions can be considered to be either linearly graded or abrupt, depending on the voltage, with a transition range covering about 2 decades of voltage. Expressions are also given for the capacitance of rectangular and circular planar junctions and for an over depleted circular planar PIN diode.
The crystal structure of semiconductors. G. ARTHUR,Electron. Compon. January (1969), p. 74. The interpretation of semiconductors usually adopted by physicists is essentially one in which the behaviour of electrons in a periodic electrostatic potential, analogous to the crystalline lattice, is considered. While this approach has obviously been extremely useful when dealing with the electrical properties of known semiconductors, it is much less useful when considering the types and chemical compositions of crystals in which semiconductivity occurs. The chemical approach only considers the distribution of electronic charge between adjacent atoms and virtually ignores the effect of the remaining atoms in the crystal. The method is, therefore, essentially qualitative but it nevertheless has been very successful in providing a framework for the classification on the basis of structure and composition of known semiconductors and for the prediction of areas where new ones might be sought.
Semiconductor compounds. H. J. GOLDSMID,Electron. Compon., January (1969), p. 59. Although semiconductor elements now receive a great deal of attention, there are still a great many uses to be found for the semiconductor compounds. This article reviews the current uses of such compounds, discusses their structure, and shows that a great deal of work remains to be done in this area of technology.
Refractory materials. B. COCKAYNE,Electron. Compon., January (1969), p. 65. The field of refractory materials in relation to semiconductors is rather a restricted area to review as very few of these materials, which can loosely be defined as those with melting points greater than 1500°C, are actually used in the manufacture of semiconductor devices. This is because most refractory materials have band gaps greater than 3eV and are classed as insulators. As a consequence, the materials which are employed at the present time are reviewed in some detail after which the difficulties associated with more speculative compounds are discussed.
151
parasitic transistor unit along with a current generator to account for the effect of the substrate. Under some operating conditions, this model is simplified to include one diode and a current generator in addition to the transistor, and in other circumstances to require only a simple current generator along with the transistor itself. The measurements necessary for determining the parameters of the complete model are identified. The pertinent constants can be obtained from the terminal currents of the device under specified operating conditions.
An automatic test set for measuring dopant concentration profiles in epitaxial films. G. W. REUTLINGER,S. J. REGAS,D. J. SIDOR and B. SCHWARTZ,Solid-St. Electron. 12 (1969), p. 31. Dopant profiles in epitaxial films can be obtained by measuring the junction capacitance, the rate of change of capacitance with respect to applied voltage, and the area o f p - n diodes made in the films. A test set has been designed and constructed which automatically measures and records on IBM cards a series of voltages and corresponding capacitances of a diode made from the film to be evaluated. Optical means are provided in the test fixture for measuring the diode area. The test set is capable of measuring up to 100 C-V points at a rate of about 15 points per rain. The total measurement time for a typical diode, including diode area measurement, is less than 4 rain. Manual C-V measurement and card punching would take at least 30 min per diode. The punched cards are processed by an IBM 7094 computer and an SC 4020 microfilm plotter to obtain the dopant profile. The computation cost is about 18 cents per diode. System and component requirements are given and the computer program in Fortran II is included.
Depletion layer and capacitance calculations for gaussian diffused junctions. P. R. WILSON, Solid-St. Electron. 12 (1969), p. 1. Expressions are derived for the voltage dependence of the depletion layer width, the maximum electric field and the capacitance of Gaussian diffused plane, cylindrical and spherical p-n junctions. These are also shown in graphical form for junctions in silicon for a ratio of surface to background concentration covering the range 102-107 . It is shown that the junctions can be considered to be either linearly graded or abrupt, depending on the voltage, with a transition range covering about 2 decades of voltage. Expressions are also given for the capacitance of rectangular and circular planar junctions and for an over depleted circular planar PIN diode.
The crystal structure of semiconductors. G. ARTHUR,Electron. Compon. January (1969), p. 74. The interpretation of semiconductors usually adopted by physicists is essentially one in which the behaviour of electrons in a periodic electrostatic potential, analogous to the crystalline lattice, is considered. While this approach has obviously been extremely useful when dealing with the electrical properties of known semiconductors, it is much less useful when considering the types and chemical compositions of crystals in which semiconductivity occurs. The chemical approach only considers the distribution of electronic charge between adjacent atoms and virtually ignores the effect of the remaining atoms in the crystal. The method is, therefore, essentially qualitative but it nevertheless has been very successful in providing a framework for the classification on the basis of structure and composition of known semiconductors and for the prediction of areas where new ones might be sought.
Semiconductor compounds. H. J. GOLDSMID,Electron. Compon., January (1969), p. 59. Although semiconductor elements now receive a great deal of attention, there are still a great many uses to be found for the semiconductor compounds. This article reviews the current uses of such compounds, discusses their structure, and shows that a great deal of work remains to be done in this area of technology.
Refractory materials. B. COCKAYNE,Electron. Compon., January (1969), p. 65. The field of refractory materials in relation to semiconductors is rather a restricted area to review as very few of these materials, which can loosely be defined as those with melting points greater than 1500°C, are actually used in the manufacture of semiconductor devices. This is because most refractory materials have band gaps greater than 3eV and are classed as insulators. As a consequence, the materials which are employed at the present time are reviewed in some detail after which the difficulties associated with more speculative compounds are discussed.