METHOD IN THE FABRICATION OF A SILICON BIPOLAR TRANSISTOR

摘要

In the fabrication of a silicon bipolar transistor, a method is disclosed for forming base regions and for opening an emitter window, comprising the steps of: providing a silicon substrate (1) with device isolation (3); forming a first base region (5) in or on top of said substrate; forming a thin layer of oxide (7) on said first base region; forming a layer of silicon (9) on top of said thin oxide layer, said silicon layer is to be a second base region; ion implanting said silicon layer; forming a layer of a dielectric (11) on top of said silicon layer, said dielectric is to isolate base and emitter regions of said transistor; patterning the hereby obtained structure in order to define the emitter window (15); etching the structure inside said defined emitter window area and through the dielectric and silicon layers, wherein the thin oxide layer is used as etch stop, thus forming the emitter window; and subsequently heat treating the structure and thus break up the oxide such that the first and second base regions will contact each other.