Method for manufacturing a semiconductor material including a semi-polar III-nitride layer

Method for manufacturing a semiconductor material including a semi-polar III-nitride layer from a starting substrate including a plurality of grooves periodically spaced apart by a distance L2, each groove including a first inclined flank of crystallographic orientation C (0001) and a second inclined flank of different crystallographic orientation, a first inclined flank of a groove and a second inclined flank of an adjacent groove forming a crenelation having a top overhung by a mask cap,

• the method comprising the phases consisting in:
• forming first III-nitride crystals on the first inclined flanks of the grooves, the growth parameters of the first III-nitride crystals being adapted to favor lateral growth of said first III-nitride crystals:
• the growth firstly inducing triangular cavities formed between the substrate and two adjacent first III-nitride crystals, a triangular cavity having a base, two walls and a vertex, the base corresponding to the substrate, a wall corresponding to a first III-nitride crystal, another wall corresponding to said adjacent first III-nitride crystal, and the vertex corresponding to a beginning of intersection between said two adjacent first III-nitride crystals, a presence of the mask cap avoiding parasitic growth on the area covered by the mask,
• and then inducing an overlapping between adjacent first III-nitride crystals, forming extended cavities situated above the triangular cavities, starting from the vertex of the triangular cavities and in line with the overlapping areas between the first III-nitride crystals in meeting planes between the first III-nitride crystals, at an intersection between two adjacent overlapping first III-nitride crystals;
• forming a two-dimensional III-nitride layer on III-nitride crystals formed beforehand.