Abstract: A method of forming alignment marks, each alignment mark including a plurality of fiducials, includes providing a III-V compound substrate having a device region and an alignment mark region. The method also includes forming a first hardmask in the device region and a hardmask structure in the alignment mark region, etching a first surface portion of the III-V compound substrate to form a plurality of trenches in the device region, and epitaxially regrowing a semiconductor layer in the trenches. The method further includes forming a second mask in the device region and a patterned structure in the alignment mark region. The patterned structure includes a set of masked regions corresponding to the plurality of fiducials and a second set of openings. The method also includes forming the plurality of fiducials.

Abstract: A method of forming regrown fiducials includes providing a III-V compound substrate having a device region and an alignment mark region. The III-V compound substrate is characterized by a processing surface. The method also includes forming a hardmask layer having a first set of openings in the device region exposing a first surface portion of the processing surface of the III-V compound substrate and a second set of openings in the alignment mark region exposing a second surface portion of the processing surface and etching the first surface portion and the second surface portion of the III-V compound substrate using the hardmask layer as a mask to form a plurality of trenches. The method also includes epitaxially regrowing a semiconductor layer in the trenches to form the regrown fiducials extending to a predetermined height over the processing surface in the alignment mark region.