Implications of ion implantation technology on ion implanted active devices in silicon

The use of ion implantation to make integrated devices in silicon implies a good knowledge of the behavior of various parts of the device. This paper deals with three main topics: First the electrical characteristics of implanted diodes are described and their variations as a function of annealing temperature lead to a physical model taking into account the anisotropy of impurity concentration gradients. Second, experimental conditions before, during and after implantation are shown to have a strong influence on the quality of the final device, particularly on the value of the reverse leakage current. Third, effects of bombardment on silicon dioxide layers are studied. It is found that recovery of the layers is generally complete after a 300°C annealing.

Contributions of these various parameters to the overall electrical characteristics of ion implanted self-aligned MOS transistors are finally considered. Substantial increase in the maximum oscillation frequency and reduction of the active surface areas of the device are the most evident advantages of using ion implantation technology.