Tuning electrical properties of Au/n-InP junctions by inserting atomic layer deposited Al2O3 layer

In order to modulate the electrical properties of Au/n-InP contacts, the insertion of an Al2O3 layer deposited by atomic layer deposition (ALD) was employed. All the samples with an Al2O3 layer showed the increased barrier height compared to the sample without Al2O3 layer. The barrier height was also found to be almost constant regardless of the Al2O3 thickness. Analysis on the reverse bias current revealed that the dominant current transport is Poole-Frenkel emission for all the samples with an Al2O3 layer, indicating that the defects are generated in the Al2O3 layer. Our results suggest that the metal induced gap states (MIGS) or interface dipole effects did not play major role in the Au/Al2O3/InP junction properties. Rather, the removal of native oxide and the termination of dangling bonds by ALD process determined the modulation of barrier heights.