Influence of the Oxidant on the Chemical and Field-Effect Passivation of Si by ALD Al[sub 2]O[sub 3]

Differences in Si surface passivation by aluminum oxide Al 2 O 3 films synthesized using H 2 O and O 3 -based thermal atomic layer deposition ALD and plasma ALD have been revealed. A low interface defect density of D it = 10 11 eV -1 cm -2 was obtained after annealing, independent of the oxidant. This low D it was found to be vital for the passivation performance. Field-effect passivation was less prominent for H 2 O-based ALD Al 2 O 3 before and after annealing, whereas for as-deposited ALD films with an O 2 plasma or O 3 as the oxidants, the field-effect passivation was impaired by a very high D it .