Single high temperature step selective emitter structures using spin-on dopant sources

The selective emitter provides a solution to the conflicting optical and electrical requirements on the emitter diffusion for a silicon solar cell. The disadvantage of this structure is an increase in the number of high-temperature processes. A new method using spin-on doped and undoped oxides has enabled the selective emitter to be manufactured in one high temperature process. This method provides independent control over the two diffusion strengths via the dopant concentration of the spin-on oxides. A key feature of this method is the out-sourcing from a doped oxide to produce a quality heavy diffusion on a neighbouring device without the use of a sacrificial wafer.