Method of making MOS transistor with high doping gradient under the gate

摘要

The invention is directed to a method of manufacturing an area of a first type of conductivity extending a depth into a semiconductor substrate and having a doping gradient as a function of the depth into the semiconductor substrate. The method comprises acts of providing a semiconductor substrate of the first type of conductivity; implanting nitrogen in an upper surface of the semiconductor substrate, with a dose in a range of between approximately 5.1013 and 5.1015 at./cm2, annealing the semiconductor substrate; and growing an epitaxial layer on the substrate of the first type of conductivity having a doping level lower than the semiconductor substrate.