Characteristics of iron doped Pt-InAlAs Schottky diodes grown by LP-MOCVD using ferrocene

Iron doped InAlAs layers were grown by MOCVD with the purpose of improving the electrical properties of this material. Photoreflectance studies clearly showed the increase of deep traps by introducing iron into the layers. Pt-Schottky diodes were fabricated on undoped and iron doped InAlAs with various iron concentrations and device parameters were extracted to reveal the impact of iron concentration on the electrical characteristics. Although iron doped layers showed lower Schottky barrier height, extremely high reverse breakdown voltage of ~90 V could be obtained with properly doped materials. The results showed that the electrical properties of InAlAs can be greatly improved if an appropriate level of iron doping is employed. Beyond certain level of ferrocene flow, the material starts presenting less pronounced semi-insulating characteristics, possibly due to the presence of iron precipitates. Low frequency noise current spectra of iron doped InAlAs showed a Lorentz-shaped spectrum near ~40 Hz suggesting an increased presence of traps with high activation energy in InAlAs:Fe