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Phonon cascade theory
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ABSTRACTS OF PAPERS TO APPEAR IN J. PHYS. CHEM. SOLIDS (Received 29 March 1966) (Revised 6 June 1966)
Vol. 4, No. 8
(Received 28 April 1966) (Revised 10 June 1966)
4. BARRIER ENERGIES IN METAL-SILICON DIOXIDE-SILICON STRUCTURES. B. E. Deal, E. H. Snow and C. A. Mead (Fairchild Semiconductor Research and Development Laboratory, Palo Alto, California).
6.
Metal-silicon dioxide barrier energies have been determined for six metals, Ag, Al, Au, Cu, Mg and Ni, deposited on thermally oxidized silicon. Results obtained by two different methods, the photoemission technique and the MOS capacitance-voltage technique, are in excellent agreement with one another. Values of the barrier energy iM range from 2. 3 ev for Mg to 4.2 ev for Ag and are roughly proportional to the electronegativities of the metals. The silicon-silicon dioxide energy (measured from the silicon valence band) has also been determined and was found to be 4. 35 ev independent of silicon orientation or type.
Charge carrier scattering mechanisms in n-type epitaxial GaP have been examined. An analysis of experimental Hall mobility-temperature curves has been made in terms of polar mode, acoustic mode, ionized impurity, and “space charge” scattering. An upper range on the electron mobility expected at room temperature in epitaxial GaP has2/volt been deduced to be sec. From this between 150 and cm12 e-v has work, a value of 174 about been deduced for the deformation potential in epitaxial GaP. The “space charge” factor [N,A ~ = 10 to 5 x 10~where N, is the number of “space charge” centres and A is the scattering cross-section. N, is of the order of 1015/cm3andA ~-~10’~ cm2.
(Received 2 May 1966) (Revised 7 June 1966) 5. PHONON CASCADE THEORY. E. F. Smith and P. T. Landsberg (Department of Applied Mathematics and Mathematical Physics. University College, Cathays Park, Cardiff.) A generalized formulation is given of the Lax electron cascade capture model. An electron capture cross-section is obtained, via an essentially classical argument, in terms of quantum mechanical transition probabilities, which may include various suitable electronboson interactions. The electronic potential energy, in the presence of an impurity centre, has been assumed to behave as r~. Crosssections have been obtained for electron capture with emission of either acoustic or optical phonons. In the latter case computations have been made yielding new cross-sections for both neutral (n=4) and Coulomb attractive centres (n=1), in germanium and silicon. The “sticking probabilities” were taken from previous literature. When comparable with earlier work, the cross-sections obtained are smaller (by at most a factor 10). The present treatment is distinguished from earlier ones by systematically confining the wave vectors of the emitted phonons to the first Erillouin zone. New estimates mclude cross-sections for electron capture by neutral centres in silicon, with optical phonon emission, over a range of temperatures.
ELECTRON SCATTERING MECHANISMS IN N-TYPE EPITAXIAL GaP. A, S. Epstein (Monsanto Company, Central Research Department, 800 North Lindberg Boulevard, St. Louis, Missouri.)
Good agreement has been found between Hall effect analysis and spectroscopic emission analysis for the concentration of the shallow donor, silicon. (Received 11 April 1966) (Revised 6 June 1966) 7.
GALVANOMAGNETIC EFFECTS IN SINGLECRYSTAL ZrB 2. John Piper (Union Carbide Research Institute, Tarrytown, N. Y.)
The magnetoresistance and Hall effect of ZrB2 crystals with resistivity ratios (p~ / P4. 2) of 100 are studied over the temperature range 1. 3-300°K, at magnetic fields to 12. 7kG. Room-temperature resistivities of the samples are 2. 9-3. 4 iohm—cm. At 4.2 °Kthe maximum observed magnetoresistance (~~/ Po) is 45. The Hall coefficients approach constant values in the high-field region and the magnetic field dependence of the magnetoresistance is approximately quadratic. No sharp minima in the orientation dependence of the transverse magnetoresistance are observed: thus ZrB2 behaves like a compensated semimetal with no open orbits in its Fermi surface. Using Hall and magnetoresistive coefficients the effective electron concentration is found to be 0. 06 per unit cell. The mobilities of the electrons and holes are of the same order of magnetude.
ABSTRACTS OF PAPERS TO APPEAR IN J. PHYS. CHEM. SOLIDS (Received 29 March 1966) (Revised 6 June 1966)
Vol. 4, No. 8
(Received 28 April 1966) (Revised 10 June 1966)
4. BARRIER ENERGIES IN METAL-SILICON DIOXIDE-SILICON STRUCTURES. B. E. Deal, E. H. Snow and C. A. Mead (Fairchild Semiconductor Research and Development Laboratory, Palo Alto, California).
6.
Metal-silicon dioxide barrier energies have been determined for six metals, Ag, Al, Au, Cu, Mg and Ni, deposited on thermally oxidized silicon. Results obtained by two different methods, the photoemission technique and the MOS capacitance-voltage technique, are in excellent agreement with one another. Values of the barrier energy iM range from 2. 3 ev for Mg to 4.2 ev for Ag and are roughly proportional to the electronegativities of the metals. The silicon-silicon dioxide energy (measured from the silicon valence band) has also been determined and was found to be 4. 35 ev independent of silicon orientation or type.
Charge carrier scattering mechanisms in n-type epitaxial GaP have been examined. An analysis of experimental Hall mobility-temperature curves has been made in terms of polar mode, acoustic mode, ionized impurity, and “space charge” scattering. An upper range on the electron mobility expected at room temperature in epitaxial GaP has2/volt been deduced to be sec. From this between 150 and cm12 e-v has work, a value of 174 about been deduced for the deformation potential in epitaxial GaP. The “space charge” factor [N,A ~ = 10 to 5 x 10~where N, is the number of “space charge” centres and A is the scattering cross-section. N, is of the order of 1015/cm3andA ~-~10’~ cm2.
(Received 2 May 1966) (Revised 7 June 1966) 5. PHONON CASCADE THEORY. E. F. Smith and P. T. Landsberg (Department of Applied Mathematics and Mathematical Physics. University College, Cathays Park, Cardiff.) A generalized formulation is given of the Lax electron cascade capture model. An electron capture cross-section is obtained, via an essentially classical argument, in terms of quantum mechanical transition probabilities, which may include various suitable electronboson interactions. The electronic potential energy, in the presence of an impurity centre, has been assumed to behave as r~. Crosssections have been obtained for electron capture with emission of either acoustic or optical phonons. In the latter case computations have been made yielding new cross-sections for both neutral (n=4) and Coulomb attractive centres (n=1), in germanium and silicon. The “sticking probabilities” were taken from previous literature. When comparable with earlier work, the cross-sections obtained are smaller (by at most a factor 10). The present treatment is distinguished from earlier ones by systematically confining the wave vectors of the emitted phonons to the first Erillouin zone. New estimates mclude cross-sections for electron capture by neutral centres in silicon, with optical phonon emission, over a range of temperatures.
ELECTRON SCATTERING MECHANISMS IN N-TYPE EPITAXIAL GaP. A, S. Epstein (Monsanto Company, Central Research Department, 800 North Lindberg Boulevard, St. Louis, Missouri.)
Good agreement has been found between Hall effect analysis and spectroscopic emission analysis for the concentration of the shallow donor, silicon. (Received 11 April 1966) (Revised 6 June 1966) 7.
GALVANOMAGNETIC EFFECTS IN SINGLECRYSTAL ZrB 2. John Piper (Union Carbide Research Institute, Tarrytown, N. Y.)
The magnetoresistance and Hall effect of ZrB2 crystals with resistivity ratios (p~ / P4. 2) of 100 are studied over the temperature range 1. 3-300°K, at magnetic fields to 12. 7kG. Room-temperature resistivities of the samples are 2. 9-3. 4 iohm—cm. At 4.2 °Kthe maximum observed magnetoresistance (~~/ Po) is 45. The Hall coefficients approach constant values in the high-field region and the magnetic field dependence of the magnetoresistance is approximately quadratic. No sharp minima in the orientation dependence of the transverse magnetoresistance are observed: thus ZrB2 behaves like a compensated semimetal with no open orbits in its Fermi surface. Using Hall and magnetoresistive coefficients the effective electron concentration is found to be 0. 06 per unit cell. The mobilities of the electrons and holes are of the same order of magnetude.