摘要 |
Methods for manufacturing a bipolar transistor semiconductor device are described, along with devices fabricated in accordance with the methods. The methods include the steps of forming a stack of layers over a semiconductor body comprising a window definition layer (18,38), a layer (20) of semiconductor material, a first insulating layer (22), and a second insulating layer (24) which is selectively etchable with respect to the first insulating layer. A trench (26) is then etched into the stack down to the window definition layer. The portion of the trench extending through the second insulating layer is widened to form a wider trench portion (28) therethrough. A window (36) is defined in the window definition layer which is aligned with the wider trench portion, and serves to define the base-collector or base-emitter junction in the finished device. |