Wet chemically thinning silicon layers in an active emitter region, especially of a high speed bipolar transistor, using an etch stop layer formed by atomic layer doping of a cover layer

摘要

Wet chemical thinning of silicon layers in a bipolar transistor active emitter region (7), using an etch stop layer (5) formed by atomic layer doping of a cover layer (3 + 9), is new. A process for wet chemical thinning of silicon layers in the active emitter region (7) of a bipolar transistor comprises carrying out an additional atomic layer doping of a cover layer (3 + 9) to a thickness of less than 3 nm to form an etch stop layer (5) which is subsequently removed with a wet chemical etchant.