The effect of deposition temperature (Tdep) and subsequent annealing time (tanl) of atomic layer deposited aluminum oxide (Al2O3) films on silicon surface passivation (in terms of surface recombination velocity, SRV) is investigated. The pristine samples (as-deposited) show presence of positive fixed charges, QF. The interface defect density (Dit) decreases with increase in Tdep which further decreases with tanl up to 100s. An effective surface passivation (SRV<8 cm/s) is realized for Tdep ≥ 200 °C. The present investigation suggests that low thermal budget processing provides the same quality of passivation as realized by high thermal budget process (tanl between 10 to 30 min).

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Doped nanocrystalline silicon thin films, in which silicon nanocrystallites are embedded in an amorphous silicon matrix, are emerging as carrier-selective contacts for next-generation silicon heterojunction solar cells.

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Plasma assisted ALD deposited hafnium oxide films are studied for silicon surface passivation. SRV < 40 cm s−1 are realized under optimised conditions.

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Thermal ALD deposited Al 2 O 3 films on silicon show a marked difference in surface passivation quality as a function of annealing time (using a rapid thermal process). An effective and quality passivation is realized in short anneal duration (B100 s) in nitrogen ambient which is reflected in the low surface recombination velocity (SRV o10 cm s À1 ). The deduced values are close to the best reported SRV obtained by the high thermal budget process (with annealing time between 10-30 min), conventionally used for improved surface passivation. Both as-deposited and low thermal budget annealed films show the presence of positive fixed charges and this is never been reported in the literature before. The role of field and chemical passivation is investigated in terms of fixed charge and interface defect densities.Further, the importance of the annealing step sequence in the MIS structure fabrication protocol is also investigated from the view point of its effect on the nature of fixed charges.

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