Oxidation barrier to vertical cavity surface-emitting laser (VCSEL) structures
Abstract
SiO2 and polyimide were investigated as oxidation barriers deposited on 50 µm stripes mesa patterns of Vertical Cavity Surface-Emitting Laser (VCSEL) structures. Scanning Electron Microscope (SEM) micrographs revealed that electron-beam deposited SiO2 served as an oxidation barrier while polyimide only hinders oxidation rate. Polyimide thickness ranges from 442–650 nm with varying spin rate and has an AlAs oxide thickness of 4.97–5.17 µm for a 25 minutes oxidation time. On the other hand, SiO2 (annealed and unannealed) thickness ranges from 300–500 Å with varying deposition rate but still remains unoxidized.