Method for forming a coating film on a facet of a semiconductor laser diode

摘要

The present invention is to provide a method for producing a semiconductor laser diode (LD) with an enhanced ESD resistance. The method includes a step for forming an aluminum film on a facet of the LD and a step for forming an aluminum oxide film on the aluminum film. The underlying aluminum film is oxidized during the formation of the aluminum oxide film to form a double aluminum oxide layer. The ratio of the oxide composition of the underlying aluminum oxide film is smaller than that of the upper aluminum oxide film.