Nonequilibrium Carrier Dynamics in GaAs Semiconductors Induced by Energetic Ions

Abstract

Energetic ions interact with semiconductor devices to produce ionization tracks that consist of dense plasmas of free carriers. These ion tracks generally penetrate through the active regions of the device into the substrate, as is shown schematically in Figure 1. The penetration depth depends on the material, the energy of the ion, and the characteristic rate of energy transfer from the ion to the material (dE/dx, commonly referred to as the stopping power). The charge created by such interactions can collect on various circuit nodes and produce transient errors in integrated circuit (IC) memories and latches that are commonly referred to as single event upsets (SEU’s), or soft fails. Single event upsets pose a serious reliability problem for space-based digital circuitry because of the large flux of energetic ions in cosmic rays and the earth’s radiation belts, and become more significant in later generation IC’s which are faster and more densely packed than their predecessors. A better understanding of basic charge collection mechanisms and their relationship to SEU phenomena is thus of considerable interest. One of the important parameters not yet fully understood is the temporal dependence of the ion-induced current transients.