Time and temperature dependences of phosphorus evolution from InP

Indium phosphide decomposes evolving phosphorus at temperatures below 360 °C in vacuum. Hence, heating in this range during processing epitaxial InGaAs films on InP substrates may lead to surface contamination of the active layer by phosphorus. This contamination can be minimized at elevated temperatures by initially depositing a passivating layer over the exposed parts of the substrate and/or active film well below the decomposition range of the substrate (e.g., at 250 °C) and then sintering the film directly or while continuing deposition at a higher temperature. The vapor pressure of phosphorus evolved from InP increases by an order of magnitude for each 45 °C increase in temperature.