A Hybrid Electron Beam Lithography Approach to Wafer Scale up of 150 mm InP Ridge Lasers

The utilization of electron beam lithography (EBL) as a wafer scale technique for the fabrication of compound semiconductor devices provides unique challenges in terms of both application and throughput. We report on wafer scale EBL in the context of fabricating edge emitting lasers on 150 mm indium phosphide (InP) substrates. A hybrid electro-optical lithography process is used to pattern typical ridge waveguide (RWG) laser structures, while overcoming some of the practical challenges associated with fabricating these devices on large wafer platforms. This technique is demonstrated to reduce patterning times by up to a factor of 20 compared to conventional EBL processes. Moreover, we motivate the application of hybrid lithography by considering the loading effect of etching 150 mm InP wafers and the benefit of transitioning to a ‘low open area’ mask geometry.