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On the absorption of infrared radiation by electrons in semiconductor inversion layers
World Abstracts on Microelectronics and Reliability tot's by scanning electron microscope. J. D. KAMM. Solid-St. Electron. 19, 921 0976). Fluctuations in doping concentration and minority-carrier diffusion length can be observed using a scanning electron microscope, in the beam inducted current mode. Semiconductors, to which a Schottky-barrier contact has been applied, may be investigated. The measurement technique is simpler than other comparable methods. The scanning image shows the fluctuations with a spacial resolution of about 10 p.m. Quantative determination of their size from the measured values is possible in certain doping ranges. Scanning images of fluctuations are presented for illustration.
Regular perimlic "exphvsions" of electron-hole drops under steady-state illumination and microwave heating. H. KROEMER. Solid-St. Commun. 20, 889 (1976). DC conductivity measurements on (strained) Ge at 4 K under steadystate illumination show that even in the presence of fairly strong steady-state microwave heating electron-hole drops continue to form, but rather than assuming a steady-state the3' "explode" periodically. The results are readily explained by--and provide corroboration for--a model by Altukhov. O H M I C contact to p-type GaP. J. PFEIFER. Solid-St. Electron. 19, 927 (1976). A study was made of the contact properties of a Au-Be eutectic and a Au-Be-Ni alloy on p-type GaP. The specific contact resistance varied from 1 x 10 3 to 7.5 × 10 5 f l c m 2 in the acceptor concentration range of 9 × 10 ~6 to 2 x 10tScm -3. In the sintering temperature range resulting in good ohmic behaviour and low contact resistance the Au-Be contacts do not form drops, whereas the Au-Be-Ni contacts became molten; even after melting they wetted the surface of the GaP well. At the temperature of sintering Be diffuses from the contact into the GaP. The diffusion of Be gives rise to an additional acceptor concentration of 5 x 10 TM to I x 1019cm -3 beneath the contact surface. Taking this into consideration the concentration-specific contact resistance relationship appears to support a field emission FE conduction mechanism.
Temperature dependence of resistivity and hole conductivity mobili~' in p-type silicon. K. Y. TSAO and C. T. SAH. Solid-St. Electron. 19, 949 (1976). A new method is employed to determine the temperature dependence of the resistivity and hole conductivity mobility of p-type silicon. This method involves the use of aluminum-on-p-Si ohmic diode and a magnesium on p-Si Schottky barrier diode on the same silicon chip. The resistivity is determined from the Al/p-Si ohmic diode. The hole concentration is evaluated from the C V data of the Mg/p-Si Schottky barrier diode. The conductivity mobility is then computed from the resistivity and ,hole concentration data. The following ranges are covered: 77-300K, 0.4 100ohm-cm and 5 x 1016-2 × 10 a4 holes/cm 3 at room temperature.
Modelling of channel enhancement effects on the write characteristics of FAMOS devices. H. C. CARD and E. L. HEASELL. Solid-St. Electron. 19, 965 (1976). Physical modelling of tloating-gate avalanche-injection MOS (FAMOS) devices in the program (write) mode is complicated by a feedback effect to the channel from the floating gate. The floating gate takes on a potential by virtue of capacitive coupling to the drain; this induces a channel near the source; the channel injects carriers into the depiction region near the drain and greatly enhances the avalanche multiplication current. This paper presents a simple method for taking account of this effect using empirical data, and thereby arriving at a first-order model of the FAMOS device. Measurements of drain current are subdivided into channel current and avalanche multiplication
23
current, and a constant hot-carrier injection efficiency is assumed. The hot-carrier (avalanche) injection current is associated with a dielectric resistivity, whose dependence on the electric field in the oxide can be approximated by a simple exponential function. Model predictions for the write characteristies of FAMOS devices are in reasonable agreement with experiment.
The properties of gate-controlled diffused microresistors. J. KASSABOV, M. VOUTOV and N. VELCHEV. Electron Technol. Warsaw 8 (3/4), 67 (1975). High resistivity boron diffusion layers, used as microresistors in MOS ICs, have been investigated. Conduction of microresistor channel and Halleffect were studied. Gate-controlled structures were used in order to obtain required value of some parameters of microresistor channel, such as average acceptor concentration, the built-in oxide layer charge and scattering factor. The total current of majority carriers in the channel is represented as a current due to the carriers in the channel and a current due to the field-effect accumulated carriers. The field dependence o f the effective mobility of surface majority carriers as well as of the average field mobility have been determined. A linear dependence has been found between the reciprocal average field mobility and total charge carrier density in the channel.
Electronic structure of semiconducting crystals under high stress. YIZl-FuI. TSAY and B. BE.',,'DOW.Solid-St. Commun. 20, 373 (1976). We prc~sent a calculation of the band structure of scmiconducting crystals under arbitrarily high stress, in which all input parameters are determined from the properties of the unstressed crystal alone. The method is applied to obtain the band structure of Ge and Si at high stress, and the strain dependence of the energies and matrix elements of a number of critical-point transitions are presented.
On the absorption of infrared radiation by electrons in semiconductor inversion layers. S. J. ALLEN and D. C. TsuL Solid-St. Commun. 20, 425 (1976). Resonances in the inversion layer for infrared fields normal to the interface do not occur at the electric subband splittings. They are shifted from the subband splittings by rt..'sonant scrccning of the infrared field. The corrections for (100) Si surfaces are shown to bc comparable to the shifts ascribed to manybody effects.
Photoconductivi~, of a semiconductor with large-scale fluctuations of electrostatic potential: a case of an impuriU' recombination. M. A. MESSERER, E. M. OMELIANOVSKY, L. TA. Ih'.RVOVA,Yt:. YA. TKATCr{ and V. I. FISTUL. Solid-St. Commun. 20, 321 (1976). It is found that a significant increase of the recombination barrier (P,oc takes place with an increase of photoexcitation level in a highly compensated semiconductor with large-scale fluctuations of electrostatic potential. The effect is caused by the dependence of the degree of filling local levels, that determines the qSr,, value, on light intensity absorbed in the impurity range of the spectrum. It makes it possible to increase the photosensitivity of the material by several orders of magnitude at the additional illumination use.
Valley degeneracy and mobility anisotropy under mechanical stress on (111) silicon inversion layers. G. DORL~A, II. GESCH and I. EISELE. Solid-St. Commun. 20, 429 (1976). Shubnikov de Haas oscillations, piezor~istance, Hall mobility, and transverse "Hall" field due to mobility anisotropy have been studied on n-channel (111) Si inversion layers. The valley degeneracy was found to be 2 between 1.7 and
Regular perimlic "exphvsions" of electron-hole drops under steady-state illumination and microwave heating. H. KROEMER. Solid-St. Commun. 20, 889 (1976). DC conductivity measurements on (strained) Ge at 4 K under steadystate illumination show that even in the presence of fairly strong steady-state microwave heating electron-hole drops continue to form, but rather than assuming a steady-state the3' "explode" periodically. The results are readily explained by--and provide corroboration for--a model by Altukhov. O H M I C contact to p-type GaP. J. PFEIFER. Solid-St. Electron. 19, 927 (1976). A study was made of the contact properties of a Au-Be eutectic and a Au-Be-Ni alloy on p-type GaP. The specific contact resistance varied from 1 x 10 3 to 7.5 × 10 5 f l c m 2 in the acceptor concentration range of 9 × 10 ~6 to 2 x 10tScm -3. In the sintering temperature range resulting in good ohmic behaviour and low contact resistance the Au-Be contacts do not form drops, whereas the Au-Be-Ni contacts became molten; even after melting they wetted the surface of the GaP well. At the temperature of sintering Be diffuses from the contact into the GaP. The diffusion of Be gives rise to an additional acceptor concentration of 5 x 10 TM to I x 1019cm -3 beneath the contact surface. Taking this into consideration the concentration-specific contact resistance relationship appears to support a field emission FE conduction mechanism.
Temperature dependence of resistivity and hole conductivity mobili~' in p-type silicon. K. Y. TSAO and C. T. SAH. Solid-St. Electron. 19, 949 (1976). A new method is employed to determine the temperature dependence of the resistivity and hole conductivity mobility of p-type silicon. This method involves the use of aluminum-on-p-Si ohmic diode and a magnesium on p-Si Schottky barrier diode on the same silicon chip. The resistivity is determined from the Al/p-Si ohmic diode. The hole concentration is evaluated from the C V data of the Mg/p-Si Schottky barrier diode. The conductivity mobility is then computed from the resistivity and ,hole concentration data. The following ranges are covered: 77-300K, 0.4 100ohm-cm and 5 x 1016-2 × 10 a4 holes/cm 3 at room temperature.
Modelling of channel enhancement effects on the write characteristics of FAMOS devices. H. C. CARD and E. L. HEASELL. Solid-St. Electron. 19, 965 (1976). Physical modelling of tloating-gate avalanche-injection MOS (FAMOS) devices in the program (write) mode is complicated by a feedback effect to the channel from the floating gate. The floating gate takes on a potential by virtue of capacitive coupling to the drain; this induces a channel near the source; the channel injects carriers into the depiction region near the drain and greatly enhances the avalanche multiplication current. This paper presents a simple method for taking account of this effect using empirical data, and thereby arriving at a first-order model of the FAMOS device. Measurements of drain current are subdivided into channel current and avalanche multiplication
23
current, and a constant hot-carrier injection efficiency is assumed. The hot-carrier (avalanche) injection current is associated with a dielectric resistivity, whose dependence on the electric field in the oxide can be approximated by a simple exponential function. Model predictions for the write characteristies of FAMOS devices are in reasonable agreement with experiment.
The properties of gate-controlled diffused microresistors. J. KASSABOV, M. VOUTOV and N. VELCHEV. Electron Technol. Warsaw 8 (3/4), 67 (1975). High resistivity boron diffusion layers, used as microresistors in MOS ICs, have been investigated. Conduction of microresistor channel and Halleffect were studied. Gate-controlled structures were used in order to obtain required value of some parameters of microresistor channel, such as average acceptor concentration, the built-in oxide layer charge and scattering factor. The total current of majority carriers in the channel is represented as a current due to the carriers in the channel and a current due to the field-effect accumulated carriers. The field dependence o f the effective mobility of surface majority carriers as well as of the average field mobility have been determined. A linear dependence has been found between the reciprocal average field mobility and total charge carrier density in the channel.
Electronic structure of semiconducting crystals under high stress. YIZl-FuI. TSAY and B. BE.',,'DOW.Solid-St. Commun. 20, 373 (1976). We prc~sent a calculation of the band structure of scmiconducting crystals under arbitrarily high stress, in which all input parameters are determined from the properties of the unstressed crystal alone. The method is applied to obtain the band structure of Ge and Si at high stress, and the strain dependence of the energies and matrix elements of a number of critical-point transitions are presented.
On the absorption of infrared radiation by electrons in semiconductor inversion layers. S. J. ALLEN and D. C. TsuL Solid-St. Commun. 20, 425 (1976). Resonances in the inversion layer for infrared fields normal to the interface do not occur at the electric subband splittings. They are shifted from the subband splittings by rt..'sonant scrccning of the infrared field. The corrections for (100) Si surfaces are shown to bc comparable to the shifts ascribed to manybody effects.
Photoconductivi~, of a semiconductor with large-scale fluctuations of electrostatic potential: a case of an impuriU' recombination. M. A. MESSERER, E. M. OMELIANOVSKY, L. TA. Ih'.RVOVA,Yt:. YA. TKATCr{ and V. I. FISTUL. Solid-St. Commun. 20, 321 (1976). It is found that a significant increase of the recombination barrier (P,oc takes place with an increase of photoexcitation level in a highly compensated semiconductor with large-scale fluctuations of electrostatic potential. The effect is caused by the dependence of the degree of filling local levels, that determines the qSr,, value, on light intensity absorbed in the impurity range of the spectrum. It makes it possible to increase the photosensitivity of the material by several orders of magnitude at the additional illumination use.
Valley degeneracy and mobility anisotropy under mechanical stress on (111) silicon inversion layers. G. DORL~A, II. GESCH and I. EISELE. Solid-St. Commun. 20, 429 (1976). Shubnikov de Haas oscillations, piezor~istance, Hall mobility, and transverse "Hall" field due to mobility anisotropy have been studied on n-channel (111) Si inversion layers. The valley degeneracy was found to be 2 between 1.7 and