Abstract: The method for fabricating a free-standing group III nitride plate (6) comprises the steps of: growing a first group III nitride layer (2) on a foreign growth substrate (1); treating the first group III nitride layer (2) so as to make it porous; growing at a growth temperature within a growth reactor (7) a second group III nitride layer (4) on the first group III nitride layer (2); and separating the second group III nitride layer (4) from the growth substrate (1) so as to form a free-standing group III nitride plate (6). According to the present invention, the step of separating the second group III nitride layer (4) from the growth substrate (6) is performed at the growth temperature and within a growth reactor (7), and comprises selective chemical etching of the porous first group III nitride layer (2).

Abstract: The method for fabricating a free-standing group III nitride plate (6) comprises the steps of growing at a growth temperature within a growth reactor (7) a first group III nitride layer (2) on a foreign growth substrate (1); growing at the growth temperature within the growth reactor (7) a second group III nitride layer (5) on the first group III nitride layer (2); and separating by laser lift-off the second group III nitride layer (5) from the growth substrate (1) so as to form a free-standing group III nitride plate (6). According to the present invention, the step of separating the second group III nitride layer (5) from the growth substrate (6) is performed at the growth temperature and within the growth reactor (7), and the method further comprises a step of treating the first group III nitride layer (1) by laser treatment at the growth temperature within the growth reactor (7) so as to provide stress relaxation areas (4) in the first group III nitride layer (2).