BARRIER HEIGHT ENHANCEMENT OF AU-SCHOTTKY JUNCTIONS ON PHOSPHINE-PLASMA TREATED N-ALLNAS

The effect of surface phosphidisation on the barrier height of Au/AlInAs (Al 48%) Schottky diodes was studied. The surface of AlInAs is treated with phosphine (PH3) plasma at 250-degrees-C. Schottky junctions formed on the phosphidised AlInAs employ a metal insulator-semiconductor (MIS) structure due to the existence of phosphorus related layers deposited on the AlInAs surface. An effective barrier height as high as 0.82 eV was successfully obtained for the Au/n-AlInAs Schottky junction with a true barrier height of 0.74 eV which is close to the ideal barrier height expected for the Schottky-Mott model. Owing to the enhanced barrier height, the reverse leakage current can be reduced by more than four-orders of magnitude in comparison with that of conventional diodes.