A semiempirical model for the cost of a commercial plasma source ion implantation (PSII) facility is presented. Amortized capital and operating expenses are estimated as functions of the surface area throughput T. The impact of secondary electron emission and batch processing time is considered. Treatment costs are found to decrease monotonically with T until they saturate at large T when capital equipment payback and space rental dominate the expense. A reasonably sized PSII treatment facility should be able to treat a surface area of 10(4) m2 per year at a cost of $0.01 per cm2.