Results are reported of measurements of the properties of diodes formed by ion implantation, and for comparison boron diffused P+N diodes of similar area close by on the same chip. The four group III acceptor impurities were implanted separately to a dose of 5 × 1015ions/cm2at room temperature into similar samples of suitably masked silicon. Boron ions were also implanted at liquid nitrogen temperature and 450°C. Annealing was limited to a maximum temperatare of 550 °C.