Low pressure plasma immersion ion implantation of silicon

Abstract

Mono-energetic plasma immersion ion implantation (PIII) into silicon can be attained only under collisionless plasma conditions. In order to reduce the current load on the high voltage power supply and modulator and sample heating caused by implanted ions, the plasma pressure must be kept low (<1 mtorr). Low pressure PIII is therefore the preferred technique for silicon PIII processing such as the formation of silicon on insulator. Using our model, we simulate the characteristics of low pressure PIII and identify the proper process windows of hydrogen PIII for the ion-cut process. Experiments are conducted to investigate details in three of the most important parameters in low pressure PIII: pulse width, voltage, and gas pressure. We also study the case of an infinitely long pulse, that is, dc PIII.