Phosphorus Diffusion, multi crystalline silicon, In-Situ Oxidation, Bulk Passivation
Summary / Abstract:
In situ oxidation during phosphorus diffusion recently has been shown to enable superior surface passivation without adding additional process steps. On the contrary, the PSG removal in diluted HF can be left out. We have optimized such a diffusion process especially for multi crystalline wafers, taking the material requirements in terms of thermal budget and cooling speeds into account, yielding emitter saturation current values below 60 fAcm-2. One of the reasons, why such process recipes have not yet gained widespread acceptance is that the performance of the accordingly diffused emitters, especially on multicrystalline wafers, may vary. To our knowledge the reasons for this behavior has not been explained, yet. We deliver an explanation by studying in depth the passivation behavior taking the front surface and bulk passivation properties into account.
Conference Programme