Degradation mechanism of Mo/GaAs_0.6P_0.4 Schottky barriers

The electrical characteristics and interdiffusion in electron‐beam evaporated Mo/GaAs_0.6P_0.4 Schottky barriers have been studied. The barrier height, ideality factor and deep trapping levels of these annealed or unannealed Mo/GaAs_0.6P_0.4 Schottky barriers are obtained by using the I–V, C–V, Rutherford backscattering spectroscopy (RBS), Auger electron spectroscopy (AES), and deep level transient spectroscopy (DLTS) analyses. A significant interdiffusion at the Mo/GaAs_0.6P_0.4 interface is demonstrated for 500 °C, 600 °C, annealed Schottky barriers. DLTS results show that there are two electron traps [E_c −(0.19±0.01) eV and E_c ‐(0.65±0.01) eV] and five hole traps [E_v +0.15 eV, E_v +(0.27±0.01) eV, E_v +(0.36±0.02) eV, E_v +(0.56±0.01) eV and E_v +0.84 eV] in existence at the metal‐semiconductor interface or in the bulk of the degraded Schottky barriers. These traps enhance the generation‐recombination effect and degrade the barrier height. RBS, AES, and DLTS results also indicate that the newly discovered hole trap E_v +0.84 eV, induced by Mo indiffusion, is believed to play a major role for Mo/GaAs_0.6P_0.4 Schottky barriers degradation.