The free Cl2thermal etching of InGaAs/InP was characterized for the fabrication of quantum well dots (QDs). The effects of mask shape on the three‐dimensional structure of the dot was investigated. Quantum dots with dimensions as small as 56 nm were fabricated using electron beam lithography and free Cl2etching. The dots were characterized using scanning electron microscopy and low temperature photoluminescence (PL). Metalorganic chemical vapor deposition (MOCVD) regrowth of InP on quantum dots of different mask shapes was investigated. The effect of non‐radiative recombination at the etched sidewall was evaluated through the normalized intensity of the PL. A red shift of the PL peak with decreasing dot sizes was observed for the as‐etched structures and attributed to the effect of residual compressive biaxial strain on the InGaAs layer. Free Cl2etching is an important etch technique forinsituetch and regrowth processes due to the high quality of the etched interface and the ability to perform selective area regrowth with a SiO2mask still present.