Fabrication of semiconductor devices

A semiconductor device fabricated by a method comprising the steps of:

• providing a semiconductor wafer comprising layers of semiconductor material, wherein the semiconductor wafer has an optically active region, and an upper surface;
• etching through the optically active region to form a facet;
• and
• simultaneously coating the facet and the upper surface of the semiconductor wafer with a coating layer comprising a dielectric material;
• wherein the semiconductor device comprises the semiconductor wafer with the facet and the coating layer, wherein the coating layer comprises the dielectric material, wherein the coating layer covers at least a part of the facet and at least a part of the upper surface of the semiconductor wafer;
• wherein the semiconductor device comprises a laser, wherein the facet is an output facet of the laser, and wherein the coating layer acts as a low reflectivity facet coating and as a passivating coating of the upper surface of the semiconductor wafer.

A semiconductor device fabricated by a method comprising the steps of:

• providing a semiconductor wafer comprising layers of semiconductor material, wherein the semiconductor wafer has an optically active region and an upper surface;
• etching through the optically active region to form a facet;
• and
• simultaneously coating the facet and the upper surface of the semiconductor wafer with a coating layer comprising a dielectric material;
• wherein the semiconductor device comprises the semiconductor wafer with the facet and the coating layer, wherein the coating layer comprises the dielectric material, wherein the coating layer covers at least a part of the facet and at least a part of the upper surface of the semiconductor wafer;
• wherein the semiconductor device comprises a photodetector, wherein the facet is an input facet of the photodetector, and wherein the coating layer acts as a low reflectivity facet coating and as a passivating coating of the upper surface of the semiconductor wafer.