Cosmic ray effects in very large scale integration

The reduced size and operational energy associated with microelectronic circuitry has created a situation wherein a cosmic ray, in a single pass, can generate a false signal or otherwise damage a circuit element. In this work an analytic expression for the event rate of false signals (soft errors) is derived, based upon the geometric probability of a cosmic-ray track occurring in the sensitive volume of a microcircuit device. The analyses show that substantial reduction in the soft error rates from heavy cosmic rays can be achieved by device designs which incorporate large operational energies and small depletion collection volumes. The permanent damage to oxide layers in metal-oxide-semiconductor devices is estimated. The special role of protons as initiators of soft errors and permanent damage is explored. These processes are then described in the context of very large scale integration electronics in earth satellite environment. Proton nonelastic scatter events which produce energetic recoiling silicon nuclei are identified as the chief cause of proton-initiated soft errors.