PURPOSE: To form in a groove an impurity-doped layer adequately controlled in terms of impurity concentration and thickness by a method wherein the combination is repeatedly applied of a process of doping a region as desired in a semiconductor substrate through a mask and another process of forming a groove within the region doped through the mask.
CONSTITUTION: Impurity is selectively driven into a substrate with the intermediary of a groove-forming mask, whereafter heat treatment is accomplished for the annealing of the region damaged during the impurity-implanting process and for the lateral diffusion of the implanted impurity. A process follows of forming a groove in the substrate by the selective etching technique with the intermediary of the groove-forming mask. The work of forming the groove is divided into several similar steps, so that impurity implantation and etching are repeatedly performed. For example, a groove- forming mask composed of a silicon nitride film 14 and silicon oxide film 15 is formed on a silicon substrate 1 and As ions are driven into the substrate 1, whereafter heat treatment is accomplished for the formation of an As-implanted layer 2. A process follows wherein the reactive ion etching technique is applied for the formation of a groove. The same is repeated for the completion of a groove provided with the As-planted layer 2 in the surface of the silicon substrate 1.
YAGI KUNIHIRO
SUNAMI HIDEO
KURE TOKUO
