Abstract: A method for manufacturing a field effect transistor including a silicon-germanium active layer and a gate oxide layer disposed on the active layer, the method including providing a stack including a substrate and a silicon-germanium first layer disposed on the substrate; forming the gate oxide layer on the stack; subjecting the stack to laser annealing so as to melt a region of the stack, the region including at least one part of the first layer, and recrystallising the molten region of the stack to obtain the silicon-germanium active layer in contact with the gate oxide layer, the active layer having a germanium concentration gradient.