A method of monitoring copper contamination. The method includes method, comprising: (a) ion-implanting an N-type dopant into a region of single-crystal silicon substrate, the region abutting a top surface of the substrate; (c) activating the N-type dopant by annealing the substrate at a temperature of 500° C. or higher in an inert atmosphere; (c) submerging, for a present duration of time, the substrate into an aqueous solution, the aqueous solution to be monitored for copper contamination; and (d) determining an amount of copper adsorbed from the aqueous solution by the region of the substrate.