Effect Of Depletion Layer Research Articles

An analysis of complex spectra from deep level transient capacitance measurements

The effect of complex sets of single- and double-level traps on deep level transient spectroscopy (DLTS) spectra is critically discussed using a numerical simulator. The simulation takes into account: the partial trap ionization, the effect of base doping, the dynamics of charged traps, and the depletion layer effect. The modeling of the capacitance transient has been extended when many traps are present. The simulator has been used for the analysis of DLTS spectra of platinum-doped and high-energy (12 MeV) electron-irradiated silicon diodes. These examples evidence how the simulation method increases the resolution of the DLTS technique. A detailed analysis of the emission kinetics of two energy level traps is also presented.

Depletion layer effects in the open-circuit- voltage-decay lifetime measurement

There is a renewal of interest in open circuit voltage decay as a technique for determining the base region minority carrier lifetime in semiconductor diodes. Although the existing theory of open circuit voltage decay provides a substantial foundation for interpreting the experimental data, major features of the decay curves of real silicon diodes cannot be satisfactorily explained unless depletion layer effects are taken into account. Theoretical decay curves are calculated to show the effects of depletion layer capacitance and recombination current on the otherwise ideal open circuit voltage decay. From these and from experimental decay curves, it is shown that each of these depletion layer effects is significant only below a threshold junction voltage that depends upon material parameters of the device.

Dependence of polar cap potential drop on interplanetary parameters

We have computed the convection potential drop across the polar cap from data obtained on high‐inclination low‐altitude satellites (AE‐C, AE‐D, S3‐3) and correlated these potential measurements with various combinations of parameters measured simultaneously in the upstream solar wind. These combinations of solar wind parameters consist of predictions based on magnetic merging theory and suggestions based on earlier empirical work. We find that the bulk of the potential drop, and its variation with interplanetary magnetic field (IMF) parameters, are successfully predicted by merging theory (to the accuracy with which they can presently be measured), but that a significant ‘background’ potential drop (∼35 kV) does not depend on IMF parameters and may thus be attributed to an unknown process other than merging. Our results indicate that small values of the IMF are amplified by a factor of 5–10 at the dayside magnetopause as a combined effect of bow shock compression and the Zwan‐Wolf depletion layer effect; correlations between IMF parameters and the polar cap potential drop are dramatically improved when this amplification is taken into account. The potential drop is better correlated with IMF parameters than with geomagnetic activity indices, presumably because the latter are affected by nonlinear reponses of the magnetosphere to the polar cap input.

High speed normally-off GaAs MESFET integrated circuit

Normally-off GaAs MESFET integrated circuits with a maximum toggle frequency of 2.4 GHz were fabricated by conventional photolithography. The unfavourable effect of the surface depletion layer due to the large state density at the GaAs surface has been reduced by adopting the recessed gate FET structure.

Evidence of magnetospheric cusp proton acceleration by magnetic merging at the dayside magnetopause

We have analyzed the energy-latitude dispersion of protons observed in the low-altitude dayside cusp on two orbits of the AE-C satellite in an attempt to reconstruct the velocity distribution of the source plasma. On the assumption that the source distribution has the form of a convecting bi-Maxwellian we have inferred the source values of V/sub parallel/(field-aligned flow velocity), T/sub parallel/(temperature parallel to the magnetic field) and (T/sub parallel /Tperpendicular/) n, where n is the number density. The inferred source parameters are consistent with a single-particle model of acceleration and injection through magnetic merging at the dayside magnetopause, provided that n is significantly smaller than the nominal fluid dynamic magnetosheath values and the ratio (T/sub parallel /Tperpendicular/) is significantly less than 1. Both of these conditions are expected as consequences of the magnetopause depletion layer effect described by Zwan and Wolf (1976) and Crooker and Siscoe (1977).