METHOD FOR FORMING SELF-ALIGNED FIELD EFFECT DEVICE BY ION IMPLANTATION

摘要

A METHOD FOR FORMING SELF-ALIGNED FIELD EFFECT DEVICE BY ION IMPLANTATION A method is provided for making a field effect transistor which comprises forming a layer of an ion beam making material on the surface of a semiconductor body of one-type conductivity. The layer has at least two adjacent apertures. At least a portion of the masking layer between these apertures and in contact with the semiconductor body surface is made of an electrically insulative material if an isolated gate field effect transistor is desired. Then a beam of ions of opposite-type conductivity is directed at the mask body at an energy and dosage sufficient to form two buried regions of opposite-type conductivity fully enclosed within said one-type body respectively beneath these two apertures. Finally, sufficient heat is applied so that the two buried regions diffuse upward until they extend respectively to the surface of the semiconductor body beneath the two apertures; the masking material must have a melting point above the temperature of the diffusion step.