FORMING IMPURITY REGIONS IN SEMICONDUCTOR BODIES BY HIGH ENERGY ION IRRADIATION, AND SEMICONDUCTOR DEVICES MADE THEREBY

摘要

22 46,767ABSTRACT OF THE DISCLOSUREImpurity regions and preferably buried impurityregions are formed of desired thicknesses and concentra-tion gradients in semiconductor bodies at a given distancefrom a selected surface of the body. A high energy ionbeam of greater than 1.0 Mev. containing ions of an impur-ity to form a desired impurity region in the semiconductorbody is formed to penetrate the body through the selectedsurface to a distance sufficient to form the impurityregion. A beam modifier is formed of a given material andnon-uniform shape to modify the ion energies on transmis-sion throughout to form the impurity region of a desiredthickness and concentration gradient at a given distancefrom the selected surface of the semiconductor body onirradiation of the semiconductor body through the selectedsurface with the transmitted high energy ion beam. Thesemiconductor body is then positioned to be irradiatedwith the high energy ion beam through the beam modifier,and the semiconductor body is so irradiated until theimpurity region of the desired thickness and concentrationgradient is formed in the body at a desired distance fromthe selected surface. Preferably, there is a predeter-mined relative movement between the beam modifier andsemiconductor body during irradiation to modulate the ionbeam as desired to form the impurity region. The semicon-ductor body is also preferably annealed after irradiationto remove detrimental electrical characteristics caused bythe irradiation from the semiconductor body,