Nonconventional quasineutral mode of carrier transport in semiconductors and semiconductor structures

Abstract

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.

Transport phenomena in intrinsic semiconductors and insulators at high current densities: Suppression of the broken neutrality drift

“…On the side adjacent to the n þ -emitter (large x values), the diffusion region changes to the region with a flat carrier distribution characteristic of the quasi-neutral mode. 7,8 At the same time, the diffusion region adjacent to the p þ -emitter, while advancing into the base, changes to the portion in which the main contribution to the carrier transport comes from the DSQD. A characteristic feature of the DSQD mode is the sharp decline in the injectedcarrier concentration.…”

“…However, it was noted that, with the field dependence of the carrier mobility taken into account, there are two additional small parameters in the problem: F=F ns < 1 and F=F ps < 1. [7][8][9] Here, F ns and F ps are characteristic drift velocity saturation fields for electrons and holes, respectively. Note that at F=F ns < 1 and F=F ps < 1, the field dependences of mobility in most of semiconductors (Si, Ge, SiC, GaN) are well described by the expression l i ¼ l i0 =½1 þ ðF=F is Þ (here i ¼ n; p).…”

“…[7][8][9] It has been shown that the mode of diffusion stimulated by a quasineutral drift (DSQD mode) is possible at large W/L ratios. 7 The field dependences of the carrier mobilities should also be taken into account for an adequate description of transport effects at large W/L ratios. 8,9 The effect of the factors mentioned above has been studied for structures based on doped semiconductors.…”

Вольт-Амперные Характеристики Диодов Шоттки При Больших Плотностях Тока В Условиях Инжекции Неосновных Носителей

“…Это обстоятельство приводит к уменьшению концентрации неосновных носителей вблизи перехода и, следователь-но, к возрастанию в этой области электрического поля. В таких условиях необходимо учитывать перенос носи-телей заряда в режиме диффузии, стимулированной ква-зинейтральным дрейфом (DSQD), подробно описанный и проанализированный в работах [12,13]. Как показано в работе [14] и будет продемонстрировано далее, исполь-зование граничного условия в форме, установленной в работе [16], т. е. пренебрежение третьим членом в ра-венстве (2), ведет к качественно неверным результатам.…”

“…При больших плотностях тока вольт-амперные характеристики как ДШ, так и p−n-перехода должны быть рассчитаны с учетом эффектов, выявленных и описанных недавно для p−n-переходов [12,13]. При больших значениях плотно-сти прямого тока наряду с хорошо известными диффу-зионным и дрейфовым режимами необходимо учитывать существование режима диффузии, стимулированной ква-зинейтральным дрейфом (DSQD mode) [12].…”