Determination of the oxygenation mechanism of CdTe obtained by reactive rfsputtering with magnetron in an Ar-N2O plasma

In this work we did studies to determinate the oxidation site and incorpora tion mechanism of oxygen to CdTe, when preparing CdTe:O thin films by rf re active magnetron sputtering, using a CdTe target and a controlled plasma of Ar-N2O. We study the influence in the oxygen content in films due to the v ariation of N2O partial pressure, plasma power and substrate position. We m onitored the process in situ by mass spectrometry to determinate the variat ion of present compounds when varying the N2O partial pressure and plasma p ower. Thin films composition was determinated by Auger electron spectroscop y and their structure by X-ray diffraction. We demonstrate that oxygen inco rporation has place mainly in the substrate, forming an amorphous CdTe:O hi m. We found that exists CdTe oxidation without using nitrous oxide, may be due to residual atmosphere. We demonstrate that CdTe oxidation depends on n itrous oxide partial pressure and plasma power. We found that deposition ra te of CdTe:O thin films depend on nitrous oxide interactions with CdTe in t he target and on the chamber walls. We propose a reaction mechanism to expl ain the oxygen incorporation to CdTe.