A method of manufacturing 13-nitride wafers (5a, 5b, 5c, 5d), each wafer (5a, 5b, 5c, 5d) comprising a front face and a major axis orthogonal to its front face and passing through the center of that front face said front face having a non-zero truncation angle (α1) in the vicinity of its center and truncation angle values symmetrically distributed about its major axis in a plane of symmetry containing said major axis of the wafer and a C-axis which is orthogonal to a C-orientated crystal plane and said truncation angle values decreasing toward the periphery of the wafer along said plane of symmetry when the surface opposite its front face is concave, and increasing toward the periphery of the wafer, along said plane of symmetry when the surface opposite its front face is convex, which method comprises - an epitaxial growth phase of a first layer of element 13 nitride on a starting substrate having a truncation angle of between 0.1 and 5 degrees, preferably between 0.2 and 0.8 degrees, and even more preferably between 0.3 and 0.6 degrees - a formation phase of a separation zone; - an epitaxy recovery phase, to form a second layer (5") of elemental nitride 13 on said first layer of elemental nitride 13, this epitaxy recovery phase being carried out at the end of the epitaxial growth phase and of the separation zone formation phase a spontaneous separation phase, in the separation zone, during the epitaxy recovery phase, to obtain a domed self-supported crystal of element 13 nitride extending longitudinally along a principal axis orthogonal to a growth face of said crystal and passing through the center of said growth face said domed self-supported crystal having a non-zero truncation angle and a radius of curvature of less than 25 meters, a cutting phase of said curved self-supported crystal, according to cutting planes transverse to the crystal and perpendicular to the main axis (7 - A-A') of the crystal, so as to obtain said platelets (5a, 5b, 5c, 5d) of element 13 nitride, the phase of formation of the separation zone being implemented before, after or during the epitaxial growth phase - an epitaxial growth phase of a first layer of element 13 nitride on a starting substrate having a truncation angle of between 0.1 and 5 degrees, preferably between 0.2 and 0.8 degrees, and even more preferably between 0.3 and 0.6 degrees - a formation phase of a separation zone; - an epitaxy recovery phase, to form a second layer (5") of elemental nitride 13 on said first layer of elemental nitride 13, this epitaxy recovery phase being carried out at the end of the epitaxial growth phase and of the separation zone formation phase a spontaneous separation phase, in the separation zone, during the epitaxy recovery phase, to obtain a domed self-supported crystal of element 13 nitride extending longitudinally along a principal axis orthogonal to a growth face of said crystal and passing through the center of said growth face said domed self-supported crystal having a non-zero truncation angle and a radius of curvature of less than 25 meters, a cutting phase of said curved self-supported crystal, according to cutting planes transverse to the crystal and perpendicular to the main axis (7 - A-A') of the crystal, so as to obtain said platelets (5a, 5b, 5c, 5d) of element 13 nitride, the phase of formation of the separation zone being implemented before, after or during the epitaxial growth phase a spontaneous separation phase, in the separation zone, during the epitaxy recovery phase, to obtain a domed self-supported crystal of element 13 nitride extending longitudinally along a principal axis orthogonal to a growth face of said crystal and passing through the center of said growth face said domed self-supported crystal having a non-zero truncation angle and a radius of curvature of less than 25 meters, a cutting phase of said curved self-supported crystal, according to cutting planes transverse to the crystal and perpendicular to the main axis (7 - A-A') of the crystal, so as to obtain said platelets (5a, 5b, 5c, 5d) of element 13 nitride, the phase of formation of the separation zone being implemented before, after or during the epitaxial growth phase