| 摘要 |
Fabrication of a bipolar transistor with a super self-aligned vertical structure of which the emitter 34, the base 32 and the collector 31 are vertically self-aligned, the fabrication method comprising the steps of forming a conductive buried collector region 22 in a silicon substrate 21 by using ion-implementation of an impurity and thermal-annealing; sequentially forming several layers 23 to 28; selectively removing the nitride and polysilicon layers 27, 28 to form a pattern; sequentially forming a silicon oxide layer 29, a nitride layer (17, Fig. 3a) and a silicon oxide layer (18) theron; forming a patterned photoresist layer thereon to define active and inactive regions and removing several layers on the active region to form an opening; forming a side wall (19, Fig. 3b) on both sides of the opening; forming a collector 31 on a surface portion of the buried collector region 22 up to a lower surface of the polysilicon layer 28; removing the side wall (19) and the third nitride layer (17) to expose a side surface of the second polysilicon layer 28; selectively forming a base 32 on an upper surface of the collector including a side surface of the polysilicon layer; forming side wall oxide layer 33 on both sides of the base and the silicon oxide to define an emitter region; forming an emitter 34 on the base 32 and forming electrodes 36 thereon. In the method, an active region is defined by a photolithography, and thereby a trench isolation acting as factors of lowering in integration and device-performance can be omitted in the method. As a result, fabrication sequence can be simplified and integration can be improved. <IMAGE>
|
