THE INFLUENCE OF METAL WORK FUNCTION ON ELECTRICAL-PROPERTIES OF METAL A-SIC-H SCHOTTKY DIODES/

Electrical properties of Schottky diodes on rf sputtered a-SiC:H thin films for different metals (Mg,In,Al,Pd) were investigated. The M(=Mg, In,Al,Pd)/a-SiC:H Schottky diodes were found to exhibit very good rect ification properties, with a turn-on voltage varying from 0.4 to 0.8 V , depending on the toy metal used, and a reverse current density lower than 10(-9)A/cm(2) with a reverse break down voltage, V-B, approximat ely equal to 15 V. The ideality factor, eta, was found to be 1.3 +/- 0 .1. This, combined with the temperature dependence of I-V characterist ics, indicates that thermionic emission is most likely the dominant tr ansport mechanism. A linear increase of barrier height at room tempera ture, phi(bRT), with increasing metal work function, phi(m), was obtai ned, suggesting that a-SiC:H exhibits the same type of conductivity (n -type) as that found for non-hydrogenated a-SiC. Pd/a-SiC:H Schottky d iodes were found to exhibit linear room temperature log I vs V charact eristics, over eight orders of magnitude, making these devices suitabl e for many applications. (C) 1997 Elsevier Science Ltd.