Abstract: Method of fabrication of a semiconductor substrate including fabrication of a semiconducting layer such that a first part of the semiconducting layer comprises a compressively strained semiconductor and such that a second part of the semiconducting layer comprises a material different from the compressively strained semiconductor. The second part of the semiconducting layer is located in a principal plane of the semiconducting layer in contact with at least two opposite edges of the first part of the semiconducting layer. The method further includes etching of a trench through the semiconducting layer, delimiting the first part of the semiconducting layer and portions of the second part of the semiconducting layer located in contact with the opposite edges of the first part of the semiconducting layer, relative to the remaining part of the semiconducting layer.