Plasma assisted atomic layer deposited hafnium oxide films for silicon surface passivation

摘要

The purpose of this paper is to investigate silicon surface passivation using plasma assisted atomic layer deposited hafnium oxide films, which is an area that is not very well explored. The effect of oxide thickness and post deposition annealing is investigated. At intermediate injection levels, effective surface recombination velocity below 40 cm s(-1) is achieved in n-type c-Si, demonstrating a good level of surface passivation after 12 min of annealing in nitrogen ambient. The capacitance-voltage characteristics of the MOS capacitor show that effective oxide charges in annealed films are high, as compared to as-deposited films, whereas, the interface defect density decreases with annealing (similar to 10(12) eV(-1) cm(-2)). A combination of chemical and field effects leads to good quality silicon surface passivation.