A method for fabricating a non-planar heterostructure field effect
transistor using group III-nitride materials with consistent repeatable
results is disclosed. The method provides a substrate on which at least
one layer of semiconductor material is deposited. An AlN layer is
deposited on the at least one layer of semiconductor material. A portion
of the AlN layer is removed using a solvent to create a non-planar region
with consistent and repeatable results. The at least one layer beneath
the AlN layer is insoluble in the solvent and therefore acts as an etch
stop, preventing any damage to the at least one layer beneath the AlN
layer. Furthermore, should the AlN layer incur any surface damage as a
result of the reactive ion etching, the damage will be removed when
exposed to the solvent to create the non-planar region.