Excellent silicon surface passivation using dimethylaluminium chloride as Al source for atomic layer deposited Al_2O_3

摘要

We demonstrate that the surface passivation of crystalline silicon and thermal stability of atomic layer deposited (ALD) Al_2O_3 can be substantially improved by replacing the conventional aluminium precursor trimethylaluminium (TMA) with low-cost dimethylaluminium chloride (DMACl). A film thickness as low as 6 nm is enough to result in a minority carrier lifetime above 1 ms after high temperature firing step. In addition, optimal ALD DMACl + H_2O process temperature and the film growth rate are comparable to the conventional TMA-based process. Thus, DMACl appears to be a potential alternative precursor for mass production with much lower chemical cost and yet excellent passivation performance.