Electrical characterization of CdS passivation on InP

InP surface passivation has been realized by a convenient chemical bath deposition (CBD) of a thin CdS layer. For comparison, samples without any treatment and with only a thin SiO/sub 2/ layer were also prepared. Also studied was the effect of a thin layer of SiO/sub 2/ deposited immediately after the CdS deposition. Schottky contacts were made on the CdS-passivated InP by electron-beam deposition of Ti/Au. Electrical characterization was conducted by current-voltage (I-V) measurements. It was found that the electrical performance of the Schottky contacts of the CdS-passivated samples was improved significantly. The thickness (deposition time) of the CdS strongly affects the device electrical performance. The additional SiO/sub 2/-on-CdS layer plays a key role in the process of InP surface passivation. Post-treatment in the CdS deposition process also significantly improves the surface morphology and electrical properties.