Abstract: A method of producing semiconductor devices having high reverse blocking ability comprising initially forming grooves in at least one major surface of a semiconductor disc of a first conductivity type according to a pattern which subdivides the disc into areal sections capable of being separated into individual device-containing semiconductor wafers and then subjecting the disc to a diffusion process to provide in each section a sequence of layer type zones of different conductivities which form at least one pn-junction and with one of the layer zones being a highly resistive zone, and to provide a zone of single conductivity type passing through the entire disc in the profile region of each of the grooves. A recess is then formed in each section of the major surface which is adjacent the pn-junction which is to be stressed in the reverse direction during use of the intended device and adjacent to each of the grooves.