Molybdenum Contamination in BF2 High Current Ion Implantation Causing PNP Beta Variability CFM/Contamination Free Manufacturing

High current implantation ion source components constructed of molybdenum provide a source of contamination in BF2 implants. The molybdenum species, Mo-98(2+), is unintentionally co-implanted during the (BF2+)-B-11-F-19 implantation due to its identical charge-to-mass ratio. In this paper, the impact of molybdenum contamination on PNP beta device performance is explored. Secondary Ion Mass Spectroscopy (SIMS) was performed to measure the molybdenum concentrations in the substrate and to understand the P+ BF2 implant disk run variability. A mechanism is described to explain the molybdenum contamination and its impact on PNP beta degradation. Molybdenum contamination was reduced to acceptable levels at the P+ Collector/Emitter implant and P-Buried Layer implant by reducing the beam current. The results showed the PNP Beta increased by 18% by reducing the contamination. Suggestions to reduce or eliminate Molybdenum contamination in a high volume manufacturing environment are discussed including optimizing the BF2 implant recipe to produce lower Mo-98(2+). The risks and challenges are also reviewed.