Charge Collection by Drift during Single Particle Upset

An improved analytical model for the drift charge collection during a single particle upset is developed. The model is based on the assumption that initially the plasma column created by an energetic particle is spread by the ambipolar diffusion. Then the collection occurs via the ambipolar drift process at the outer radius of the plasma column where the plasma density drops to a value comparable to the substrate doping. In agreement with experimental data the model predicts that the collected charge increases with the decrease in the substrate doping. A good fit to experimental data for beryllium, oxygen and copper ions is obtained for Si n+p and p+n samples.