to a photomask pattern employing conventional photolithographic techniques typically an ultraviolet about 365 nm exposure of 3 4 mw cm 2 for 30 seconds is employed alternatively a beam of electrons having energies on the order of about 10 to 100 kv is typically employed the photoresist film is then developed in developer commonly in an aqueous solution in a ratio of 1 1 for about 30 seconds as is conventional for a positive photoresist the exposed portions are removed by the developer for a negative photoresist the unexposed portions are removed in the processing of gallium arsenide diode lasers an oxide film is sometimes formed over the gallium arsenide layer the oxide film may be either a native oxide grown to a thickness of about 1250 a or a silicon oxide sio 2 layer that is grown to a thickness of about 1000 a in the case of a native oxide film during developing of the photoresist the unwanted portions of photoresist are removed along with portions of the native oxide that are exposed thus exposing portions of the p gaas surface for subsequent metallization a post cure is then optionally performed depending on the severity of the metallization process with respect to the remaining photoresist and native oxide films the metallization process is conventional and forms no part of this invention electroplating is a comparatively severe process since the process tends to lift portions of the photoresist film and.