Strong improvement of diffusion length by phosphorus and aluminum gettering

摘要: The minority carrier diffusion length in polycrystalline silicon has been strongly improved by using several gettering processes. These processes include different surface treatments followed conventional thermal annealing (CTA) performed at temperatures between 800 and 950 °C. n+p structures with a back lapped exhibit maximum increase of the from 35 to 140 μm for 45 min duration 900 realization field (BSF) on aluminum deposition CTA cycle 950 °C, slow cooling rate (2 °C/min) induces strong additional gettering, resulting up 350%.