Reduction of As carryover by PH3 overpressure in metalorganic vapor-phase epitaxy

InGaAs/InP superlattices were grown to analyze the As carryover at the InP-on-InGaAs interface in metalorganic vapor-phase epitaxy. The analysis through the double crystal X-ray diffractometry and the subsequent simulation revealed that a InAsP transient layer is formed at the interface due to As carryover to the InP layer. The change of PH3 flow rate during the growth interruption is found to be effective in controlling the desorption of As from the deposits on the reactor wall. It is believed that the increase of PH3 flow rate accelerates the As desorption and thus the As depletion is completed in a shorter time. In addition, the increased amount of desorbed As helps to protect the InGaAs surface during PH3 flow. The high PH3 flow and the corresponding interruption time provide nearly As-free InP-on-InGaAs interface.