A new method of InP substrate cleaning is presented for molecular beam epitaxy (MBE). It is based on the congruent sublimation of InP at a temperature of 380 ± 50 ° C and is phosphorous-beam free, so that the substrate cleaning can be carried out in the preparation chamber with no phosphorous K-cell provided. This is important to keep the growth chamber free from degassing during substrate preparation. InGaAs-InAlAs MQW epilayers grown on InP substrates cleaned by the present method were characterized crystallographically, optically and electronically, demonstrating that the quality is as good as that of those grown on a substrate cleaned by the conventional method. © 2005 Elsevier B.V. All rights reserved.