Influence of magnetic field on magnetized hydrogen plasmas in plasma immersion ion implantation

Abstract

Plasmas with higher density and better uniformity are produced using an improved planar radio frequency (RF) inductively coupled plasma (ICP) configuration in plasma immersion ion implantation (PIII). An external Helmholtz magnetic field coil is used to produce static axial magnetic field in the plasma discharge chamber. The RF power can be effectively absorbed by magnetized plasma in the presence of the external magnetic field. The influence of external magnetic field polarization direction on the RF power absorption and plasma density is experimentally investigated. Since the plasma generation and processing chambers are separated, plasma extinction due to the plasma sheath touching the chamber wall in high-energy PIII can be avoided. The ion density uniformity is better than or equal to 7% in the processing chamber at low pressure (0.5 mTorr). Low-pressure, high-energy and high-uniformity ion implantation can be achieved with several gauss external axial magnetic field.