Ion implantation of boron and phosphorus into silicon yields material that has electrical characteristics that are similar to silicon doped by conventional techniques. These results, and the ability to control and reproduce both the number of dopant atoms and their depth distribution, have been used to considerable advantage to fabricate both discrete devices and integrated circuits by ion implantation. We have made resistors, junction diodes, hyperabrupt diodes, IMPATTS, and field effect transistors. The narrow spread in the operating characteristics and the excellent performance of these devices, illustrate the advantages gained by using ion implantation as a step in the fabrication of devices.