Process for fabricating a lateral transistor having self-aligned base and base contact

摘要

A lateral transistor structure having a self-aligned base and base contact is provided, together with a method for fabricating such a structure in which the base width is controlled by lateral diffusion of an impurity through a polycrystalline silicon layer. The resulting zone of impurity changes the etching characteristics of the layer and permits use of a selective etchant to remove all of the layer except the doped portion. The doped portion may then be used as a mask to define the base electrical contact, which in turn is used to provide a self-aligned base for the transistor. Dopants introduced on opposite sides of the base electrical contact create the emitter and collector.