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It is shown that, in addition to the diffusion and broken neutrality drift (BND) modes well-known for insulators and very lightly doped semiconductors, the quasineutral drift (QND) mode is possible. The transition from the BND to QND mode is accompanied by the appearance of a portion with a very sharp current rise in the current-voltage characteristic. This effect is observed in a new type of semiconductor detectors (CIDs, Current Injected Detectors) of high-intensity neutron and proton radiation, suggested, in particular, for Large Hadron Collider. The effect is unambiguously attributed now to the presence of radiation-induced deep centers in a semiconductor. It is shown, however, in this paper that the effect of a very sharp rise in current upon a slight increase in voltage is even possible when there are no deep centers. An equation adequately describing the possible transport modes in intrinsic semiconductors and insulators is derived. The results of an analytical study are confirmed by an adequate simulation. [ABSTRACT FROM AUTHOR]

It is demonstrated that, in addition to the well-known quasineutral modes of carrier transport, i.e., those of quasineutral diffusion and quasineutral drift, a quasineutral mode of diffusion stimulated by quasineutral drift (DSQD) is possible. An equation that describes this mode is derived and the principal specific features of the mode are examined analytically. In particular, an analytical expression for the current-voltage (I-V) characteristic is obtained for the case when just DSQD governs the carrier transport. The analytical results obtained are verified and confirmed by a detailed simulation. [ABSTRACT FROM AUTHOR]

Fast and ultrafast switch-on processes in p-n diodes at very high current densities j and very short current rise time τ0 have been investigated analytically. It is demonstrated that even at relatively modest values of the rate of current density rise dj/dt, the switch-on transient fundamentally differs from that in the “classical” quasineutral mode. The switch-on processes occur in modes with broken neutrality. The base resistivity is modulated by fast hole and electron waves that propagate toward each other at the maximum possible (saturation) velocities. The conditions for the appearance of fast waves have been established. Analytical expressions for the initial stage of propagation of these waves have been derived. Adequate computer simulation confirms the analytical results. [ABSTRACT FROM AUTHOR]

Electron-hole scattering (EHS) affects the operation of all bipolar semiconductor devices at a high current density. From a physical point of view, EHS has always been considered an additional "frictional mechanism" for free carriers. Because any friction is a dissipative process, the main conclusion of numerous studies devoted to EHS is that the EHS increases the forward voltage drop across semiconductor devices. As a consequence, the inclusion of EHS inevitably raises the energy loss in bipolar devices. It is shown in this paper that EHS leads to a decrease in the forward voltage drop across bipolar devices in some important cases. This decrease may be substantial from a practical point of view. [ABSTRACT FROM AUTHOR]

The parameters of electron-hole scattering (EHS) in silicon carbide (SIC) are estimated by analyzing pulsed isothermal current-voltage characteristics of 6.0 kV 4H-SiC diodes over a wide range of current densities (10[sup 0] - 10[sup 4] A/cm²) and external temperatures (293-553 K). The efficiency of EHS in SiC is approximately two times higher than that in Si and 60 times higher than that in GaAs. The EHS makes a very essential contribution to voltage drop across SiC bipolar devices at high forward current densities. [ABSTRACT FROM AUTHOR]

The effect of electron-velocity saturation on the switch-on of an n +- p- p + structure in a quasi-neutral drift mode is considered. It is shown that electron-velocity saturation substantially decelerates the flight of the electron wave across the p-typebase of the n +- p- p + structure. This effect is also manifests itself in the stage of carrier accumulation in the p base of the structure. The velocity saturation effect is stronger, the thicker the base layer and the higher the rate at which the current flowing through the structure increases. The results obtained supplement the previously suggested classical description of the propagation of a minority carrier wave across the diode base layer, which disregards the effect of carrier velocity saturation. The results of an analytical calculation are confirmed by a numerical simulation. [ABSTRACT FROM AUTHOR]