Electrical characterization of Pt-Ti/p-InGaAs/n-InP heterostructures

The electrical properties of Pt-Ti/p-InGaAs/n-InP heterostructures annealed at different temperatures were studied using deep-level transient spectroscopy and I-V-T measurements in order to evaluate the effect of the Pt/Ti ohmic contact and corresponding rapid thermal processing (RTP) temperature on the device performance. It was found that a new hole trap level of 0.89 eV was induced at temperatures above 500 degrees C but not at lower temperatures. Ti interdiffusion is believed to be responsible for this hole trap. Four electron trap levels with activation energies of 0.61, 0.45, 0.35, and 0.30 eV were observed for all samples and believed to be native defects in the InP. I-V-T measurements indicated that the current mechanisms are independent of the RTP temperatures.<>