Neutron activation analysis for calibration of phosphorus implantation dose

A feasibility study was undertaken to determine if radiochemical neutron activation analysis (RNAA) can be used to certify the retained dose of phosphorus implanted in silicon, with the goal of producing a phosphorus SRM. Six pieces of silicon, implanted with a nominal phosphorus dose of 8.5x1014 atoms·cm-2 were irradiated at a neutron flux of 1.05x1014 cm-2·s-1. The samples were mixed with carrier, dissolved in acid, the phosphorus isolated by chemical separation, and 32P measured using a beta proportional counter. A mean phosphorus concentration of (8.35±0.20)x1014 atoms·cm-2 (uncertainty=1 standard deviation) was determined for the six samples, in agreement with the nominal implanted dose