Pulse current behavior in the presence of external magnetic field in radio frequency (RF)-inductively coupled plasma (ICP) quasi-direct current plasma immersion ion implantation

Summary form only given, as follows. In plasma immersion ion implantation (PIII) processes to fabricate silicon-on-insulator (SOI) materials such as separation by plasma implantation of oxygen (SPIMOX) and ion cut/wafer bonding, long-pulse PIII (or quasi-direct current PIII) has been shown to be more superior than conventional pulsed-mode PIII. The new process reduces the amount of the implanted ions in the near surface as well as the processing time. Our former experiments on quasi-DC and DC PIII utilize a grounded conducting grid above the sample holder to avoid plasma extinction as the plasma sheath expands. Recently, we have been successful in achieving stable operation in the long-pulse PIII mode by making the distance between the sample holder and plasma source long and the plasma density relatively high. In order to intensify the plasma discharge and produce one dominant ion species in the plasma, a weak external magnetic field (B) is generated using magnetic coils around the vacuum chamber. It is observed that the discharge is enhanced but the pulse current waveforms are significantly changed with the addition of B as well. Our results further indicate that the pulse current varies with the pressure and pulse voltage. We also observe that the magnitude of the pulse current is reduced as the pulse voltage increases in some pressure ranges. This can probably be attributed to the variation of the plasma generation volume and ion motion in the expanded sheath at different pulse voltages.