COMPUTER-SIMULATION OF MASS-SELECTIVE PLASMA-SOURCE ION-IMPLANTATION

The use of plasma source ion implantation (PSII) for impurity sensitiv e substrates such as semiconductors has been slow to be adopted due to the difficulty of producing low impurity plasmas. In this work die fe asibility of producing impurity-free plasmas for PSII using a mass fil tering. technique is investigated. In this method, an ion cyclotron re sonance (ICR) cell is incorporated into a plasma processing reactor to selectively expel unwanted ions. The implementation of ICR in ion imp lantation is subject to a number of complications, such as ion-neutral collisions, plasma shielding of excitation fields, and nonhomogeneiti es of die magnetic field. A numerical simulation of ICR-based mass fil tering for PSII to investigate these effects has been developed. Mass filtering is potentially effective over a wide range of magnetic field configurations at the pressures typically used for PSII.