The response of silicon detectors to low-energy ion implantation

Studies of electrical transients in single-crystal silicon induced by discrete low-energy (sub-20 keV) ions have been carried out at 90 K, with ionization measurements and damage accumulation in the sample being investigated. Ionization studies reveal a discrepancy between experimental results and predictions from the widely used SRIM (stopping and range of ions in matter) code, one which increases with decreasing energy: a result which has previously been suggested from studies with continuous ion beams. Damage accumulation studies of the sample also demonstrate that current models of damage build-up in silicon are inadequate at such low energies, with experiments indicating that individual ions create a much larger region of decreased charge collection efficiency outside of the small amorphous cores known to be formed by such impacts.