Technology for In-house Manufacture of a Surface-emitting Semiconductor Laser (VCSEL)
Fuji Xerox manufactures vertical-cavity surface-emitting lasers (VCSELs) in-house. A VCSEL is a surface-emitting semiconductor laser that acts as a key device for fast and high-resolution copying machines and multifunction devices. VCSELs are used as the light source of the scanning-type light exposure system that is considered the core area of copying machines. A VCSEL can simultaneously write using 32 laser beams, enabling a high image quality of 2,400 dpi. In order to achieve this high image quality, all light-emitting points must have highly uniform optical power.
Fuji Xerox utilizes unique passivation and dry etching technologies to maintain consistency among the optical characteristics of all VCSEL chips, and also focuses on oxidation control (as part of the manufacturing process) to reduce differences in the optical characteristics among wafer lots. This led to the development of an original in-situ monitoring method named the Optical Probing Technique for AlAs Lateral Oxidation (OPTALO). As the oxidation process is performed in an airtight silica tube, the progress cannot be directly observed. To understand and control the progress of oxidation in real time, the OPTALO method radiates white light onto the wafer so that changes in the reflection spectrum can be observed. This method led to a significant improvement in manufacturing yield.
By manufacturing key devices used to maintain high image quality and high productivity in-house, Fuji Xerox aims to become an undisputed leader in manufacturing.
Fig. 1: VCSEL Array Element with 32 Beams Lit Simultaneously
Fig. 2: Manufacturing of VCSEL (Mounting Process)