Vertical-cavity surface-emitting lasers fabricated using a sealing of AlAs against wet oxidation

We have studied the process of sealing an exposed AlAs and the wet oxidation behavior of AlAs to prevent further wet oxidation. A critical processing step consists of the formation of an oxide surface barrier by the first wet oxidation for a short time at 390 -430 degrees C in the steam environment of previously room-ambient exposed AlAs surface. During this brief wet oxidation, a dense oxide barrier with a thickness of similar to 1 mu m is formed, which further blocks diffusing oxygen species during the second wet oxidation. The oxide surface barriers of similar to 1 mu m thickness formed at 408 degrees C and 410 degrees C have shown the best effectiveness of sealing against further wet oxidation. The effectiveness of the sealing is demonstrated through its use as a mask against wet oxidation in the fabrication of oxide-confined vertical-cavity surface-emitting lasers.