Plasma-enhanced atomic layer deposited SiO2 enables positive thin film charge and surface recombination velocity of 1.3 cm/s on germanium

The excellent field-effect passivation provided by aluminum oxide (Al2O3) on germanium surfaces relies the high negative fixed charge present in film. However, many applications, a neutral or positive would be preferred. Here, we investigate surface performance and polarity of plasma-enhanced atomic layer deposited (PEALD) silicon (SiO2) Ge. results show that even 3 nm thick PEALD SiO2 provides density (Qtot, ∼2.6 × 1011 cm−2) relatively good (maximum recombination velocity SRVmax ∼16 cm/s). When thin film is capped with an ALD Al2O3 layer, improves further low midgap interface defect (Dit) ∼1 eV−1 cm−2 achieved. By varying thickness under capping, it possible to control Qtot from virtually (∼2.8 1010 moderately (∼8.5 values. Consequently, as 1.3 cm/s obtained using optimized SiO2/Al2O3 thicknesses. Finally, origin well defects related are discussed.