ELECTROLUMINESCENT SEMICONDUCTOR DEVICES AND METHODS OF MAKING THEM

摘要

1279674 PN Junction devices WESTERN ELECTRIC CO Inc 25 June 1969 [28 June 1968] 32034/69 Heading H1K [Also in Division C4] The N-type region of a gallium phosphide electroluminescent PN junction device is doped with sufficient sulphur to give a net donor doping of from 5 Î 1016 to 2 Î 1017/c.c. and the P-type region is doped with nitrogen. A device of this type emits green light with improved efficiency and may be produced as follows: 50 grams of gallium are heated to 1000‹ C. for an hour in an evacuated quartz vessel then 5 grams of gallium phosphide and 100 Á grams of gallium sulphide are added and the vessel reevacuated, heated at 1200‹ C. for 6 hours, then cooled at 30‹ C./hour. Gallium phosphide crystals containing residual nitrogen are extracted in nitric acid and polished and etched 111 faces produced thereon. They are then disposed at the opposite end of a tipping boat to a mixture of gallium and gallium phosphide and heated at 900‹ C. in a flow of hydrogen and ammonia with a zinc containing boat maintained at 600‹ C. upstream. The boat temperature is next raised to 1040‹ C. to form a solution of zinc, nitrogen and gallium phosphide in the gallium and the boat tipped to flood the crystals. After slightly raising the temperature to cause wetting the boat is cooled to 900‹ C. over a period of 15-30 minutes. When cool the crystals are removed, heat treated in air for ¢hour at 625‹ C. and then provided with goldzinc or tin electrodes. In an alternative procedure sulphur doped N-type gallium phosphide is epitaxially grown on a nitrogen doped P-type substrate.