In this paper an analytic analysis of the breakdown voltage of an ion‐implanted junction is presented. A joined half‐Gaussian distribution of the implanted ions is used, since it gives better description of the impurity profiles. The results are based on a closed‐form solution of Poisson’s equation in the depletion region. Fulop’s average ionization coefficient is used to determine the values for the avalanche breakdown voltage as a function of implantation energy, implant dose, and substrate dopant concentration. The maximum electric field at junction breakdown is also calculated and the results are presented. Finally, the applicability and restrictions of the analysis are discussed.