Nuclear physics of cosmic ray interaction with semiconductor materials: Particle-induced soft errors from a physicist's perspective

The key issues of cosmic-ray-induced soft-error rates, SER (also referred to as single-event upset, SEU, rates) in microelectronic devices are discussed from the viewpoint of fundamental atomic and nuclear interactions between high-energy particles and semiconductors. From sea level to moderate altitudes, the cosmic ray spectrum is dominated by three particle species: nucleons (protons and neutrons), pions, and muons. The characteristic features of high-energy nuclear reactions of these particles with light elements are reviewed. A major cause of soft errors is identified to be the ionization electron-hole pairs induced by the secondary nuclear fragments produced in certain processes. These processes are the inelastic collisions between the cosmic ray particles and nuclei in the host material. A state-of-the-art nuclear spallation reaction model, NUSPA, is developed to simulate these reactions. This model is tested and validated by a large set of nuclear experiments. It is used to generate the crucial database for the soft-error simulators which are currently used throughout IBM for device and circuit analysis. The relative effectiveness of nucleons, pions, and muons as soft-error-inducing agents is evaluated on the basis of nuclear reaction rate calculations and energy-deposition analysis.