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 throughputT. The impact of secondary electron emission and batch processing time is considered. Treatment costs are found to decrease monotonically withTuntil they saturate at largeTwhen capital equipment payback and space rental dominate the expense. A reasonably sized PSII treatment facility should be able to treat a surface area of 104m2per year at a cost of $0.01 per cm2.