Ion implantation with controlled nonuniformity

Abstract

A new method of ion implantation can implant two areas of one wafer at once with controllably different doses, given a ratio of the two areas. Surface doses for a particular ratio of the two areas are calculated. A twofold-triangular waveform generator has been designed to deflect the implant beam along the x-axis. The experimental results with respect to ion implantation with controlled nonuniformity agree reasonably well with calculated results. There may be a possibility of accurate production control for ranks or classification of electrical characteristics of semiconductor devices if the doping level can be changed controllably even in one wafer.