A novel leakage current model at the bottom of the recessed field oxide associated with the effects of PN junction fringing electric fields during irradiation is presented. Analytical expressions are derived for leakage current as a function of DC bias conditions during irradiation of the substrate and of the buried layer doping levels. Values of the P/sup +/ channel stop and buried layer doping levels for leakage minimization are discussed. Experimental data for the leakage current as a function of irradiation bias and high-temperature annealing are described. Experimental data include the effects of structure nonuniformities on the leakage formation.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>