METHOD OF FABRICATING TRANSISTOR

摘要

PURPOSE:To improve the characteristics and yield of a transistor, prevent the increase of the layer resistance directly under a base electrode pickup hole and improve the insulation between an emitter and a base thereof by retaining a Si3N4 film at the periphery of an emitter impurity diffused hole and a base electrode hole portion. CONSTITUTION:An Si3N4 film 17 is formed partially on the surface of a semiconductor substrate 12. The film 17 is then removed except the peripheries of the base electrode pickup portion and the emitter electrode pickup portion by a photoetching process. The exposed surface is then thermally oxidized to form a base region 19 therein. The thermally oxidized film is then selectively removed by a photoetching process to form hole 18. An emitter region 21 is formed in the semiconductor substrate through the hole 18. Only the Si3N4 film retained at the base electrode pickup portion 22 is then removed.