The influence of the process environment on thermally induced intermixing of GaAs/AlAs/AlGaAs double barrier quantum wells is investigated by effecting different low energy reactive ion etch (RIE) surface treatments and then depositing PECVD/sputtered cap layers prior to annealing. We observe photoluminescence blue shifts, small red shifts and total intermixing, dependent on the actual combination of cap material and RIE treatment. The results indicate that the RIE surface damage is an important factor for the onset of the intermixing process and that PECVD processes may require a few monolayers thick surface disordering in order to trigger off the quantum well intermixing, even using SiO2cap layers. ©1995 American Institute of Physics.