| 摘要 |
PURPOSE: A method for fabricating a bipolar junction transistor(BJT) is provided to fabricate the BJT having an excellent characteristic by simply and easily controlling the width of a base. CONSTITUTION: A silicon-on-insulator(SOI) layer(14) is formed on an oxide layer(12) formed on a semiconductor substrate(10). A nitride layer(15) is formed on the SOI layer. A photoresist layer pattern(22) is formed on the nitride layer and is etched to form a hole(16) exposing a predetermined portion of the SOI layer. Base polysilicon(20) is stacked on the sidewall oxide layer(18) of the hole from which the photoresist layer pattern is removed and on the nitride layer. P+ ions are doped to the base polysilicon and are annealed to form an emitter(26) and a collector(28). A photoresist layer pattern is so formed that a photoresist layer is applied to the upper region of the polysilicon vertically corresponding to a region outwardly separated from both inner sidewalls of the sidewall oxide layer by a predetermined distance. The base polysilicon is selectively etched to expose the SOI layer having a type of the photoresist layer pattern so that a base(24) is formed. The photoresist layer pattern is eliminated. The resultant semiconductor substrate is annealed.
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