DEEP LEVEL TRANSIENT SPECTROSCOPY OF MO GAAS SCHOTTKY BARRIERS PREPARED BY DC SPUTTERING

DC sputtering of molybdenum allows the realization of near ideal Schottky barriers provided suitable deposition conditions are utilized. DLTS investigation shows that this kind of deposition process does not introduce damage defects if the sputtering voltage is below 2.5 kV, in our experimental conditions. The electrical characteristics get worse and a reduction in EL2 signal is evident for diodes prepared at the highest sputtering voltage. The reduction in EL2 signal is not an apparent effect related to the lowering of the barrier but it is strictly correlated to the damage due to the metal deposition process. A model, based on the outdiffusion of interstitial and antisite As, is proposed to interpret the experimental data.