Measurements of stress induced by TiOx layers on single quantum well InP based heterostructure are presented. Strain characterization has been performed by photoluminescence (PL) and micro-Raman spectroscopy. We present a comparison of the stress induced by TiOx and SiO2 layers which are commonly used as masking material for the quantum well intermixing process. Micro-Raman spectroscopy and PL revealed that TiO2 is creating a stress field in the top layers of the heterostructure, with a dependence on temperature and stressor thickness. A hysteresis phenomenon of the Raman shift has also been observed after measurements at low temperature (below 300 K) which shows that the stress created by TiOx exceeds the elastic limit of InP. On the other hand, there is no evidence that SiO2 is inducing stress. Rapid thermal annealing of samples covered with titanium oxide results in improvement of the thermal stability. (c) 2006 American Vacuum Society.