IN-SITU OPTICAL MONITORING OF ALAS WET OXIDATION USING A NOVEL LOW-TEMPERATURE LOW-PRESSURE STEAM FURNACE DESIGN

To reproducibly define small features by oxidizing AlGaAs layers, it i s essential to have good control over the oxidation reaction, We have integrated a glass viewport into a low-pressure (5 torr) cold-walled o xidation chamber to enable in situ optical monitoring of the sample du ring oxidation, To gain additional control, we reduced the oxidation t emperature to 325 degrees C, consequently slowing the oxidation rate t o 2 mu m/h, Realtime in situ optical measurements of AlAs oxidation ra tes were performed using this system and the results were compared wit h a standard model, Oxide-semiconductor distributed Bragg reflectors ( DBR's) were also fabricated and measured, yielding highly reflective m irrors suitable for vertical-cavity surface-emitting laser (VCSEL) fab rication.