Postannealing Effect on ITO/p+-GaP with a Diffused Layer

Abstract

In this study, indium tin oxide (ITO) films were deposited on p-type GaP films with a AuBe diffused metal layer to form ohmic contacts. Without the AuBe diffused into p-GaP films, the ITO deposited on p-GaP showed a non-ohmic characteristic. After the AuBe diffused, the ITO deposited on p-GaP displayed a linear current-voltage characteristic and the specific contact resistance showed 2.63 × 10−4 Ω cm2. Furthermore, the specific contact resistance could be improved to 1.57 × 10−4 Ω cm2 when the sample post-annealed at 400°C. The transmittance of ITO film almost was kept at 90% in the wavelength range of 400–700 nm after thermal annealing. These results revealed that the ITO films can be a suitable transparent current spreading layer for the fabrication of AlGaInP-based light-emitting diodes with a AuBe diffused metal layer.