An ion implanter for silicon solar cells

Abstract

A simple ion implanter suitable for doping single crystal silicon for solar cells has been constructed. The implanter uses a solid feed, “Freeman” type ion source and the beam strikes the sample directly, without any mass analysis. The maximum ion energy is 50 keV for singly charged ions. A small fraction of the beam is sampled by a simple crossed field ($\text{E>}\text{×}\text{B}$) system, to investigate its mass-composition. The system is designed primarily to produce phosphorus and antimony beams. After the radiation damage has been removed by annealing, implanted silicon wafers show low resistivity and good uniformity.