Method of forming a microelectronic device comprising, on a same support: at least one tensile strained semi-conductor zone, and at least one compressive strained semi-conductor zone, the method comprising the steps consisting in: a) forming from a stack of layers resting on a substrate and comprising at least one semi-conductor layer situated above at least one prestrained layer (102 2): at least one first semi-conductor (108 1) zone having a first critical dimension L 8 provided less than a predetermined limit length Lc, and at least one second semi-conductor zone having a second critical dimension L 9 provided greater than said predetermined limit length Lc, the first semi-conductor zone and the second semi-conductor zone being formed from the semi-conductor layer and being disjoined, the first critical dimension and the second critical dimension corresponding respectively to the smallest dimension of the first semi-conductor zone except its thickness and to the smallest dimension of the second semi-conductor zone except its thickness, b) forming one or several trenches (110, 120, 130, 140, 210, 220, 230, 240) in at least a part of the thickness of said pre-strained layer, at least one trench among said trenches being situated in the continuation of at least one first side of said first semi-conductor zone (108 1), at least another trench among said trenches being situated in the continuation of at least another side of said first semi-conductor zone (108 1), opposed to said side, the the limit length Lc corresponding to a limit value for which the mean strain of a given semi-conductor zone of said semi-conductor layer change sign from a tensile state to a compressive state and when this given zone has a first side in the continuation of a first trench of said trenches and when this given zone has a second side in the continuation of a second trench of said trenches, the limit length Lc having been determined as a function of the thickness of the layers of the stack in which the trenches are made, the method being such that first semi-conductor zone has, after step b), a strain of the same type as said pre-strained layer, said second semi-conductor zone having a strain of a type opposite to that of said pre-strained layer. a) forming from a stack of layers resting on a substrate and comprising at least one semi-conductor layer situated above at least one prestrained layer (102 2): at least one first semi-conductor (108 1) zone having a first critical dimension L 8 provided less than a predetermined limit length Lc, and at least one second semi-conductor zone having a second critical dimension L 9 provided greater than said predetermined limit length Lc, the first semi-conductor zone and the second semi-conductor zone being formed from the semi-conductor layer and being disjoined, the first critical dimension and the second critical dimension corresponding respectively to the smallest dimension of the first semi-conductor zone except its thickness and to the smallest dimension of the second semi-conductor zone except its thickness, b) forming one or several trenches (110, 120, 130, 140, 210, 220, 230, 240) in at least a part of the thickness of said pre-strained layer, at least one trench among said trenches being situated in the continuation of at least one first side of said first semi-conductor zone (108 1), at least another trench among said trenches being situated in the continuation of at least another side of said first semi-conductor zone (108 1), opposed to said side, the the limit length Lc corresponding to a limit value for which the mean strain of a given semi-conductor zone of said semi-conductor layer change sign from a tensile state to a compressive state and when this given zone has a first side in the continuation of a first trench of said trenches and when this given zone has a second side in the continuation of a second trench of said trenches, the limit length Lc having been determined as a function of the thickness of the layers of the stack in which the trenches are made, the method being such that first semi-conductor zone has, after step b), a strain of the same type as said pre-strained layer, said second semi-conductor zone having a strain of a type opposite to that of said pre-strained layer.