MANUFACTURE OF A SEMICONDUCTOR DEVICE WITH A POLY-EMITTER BIPOLAR TRANSISTOR

A method of manufacturing a semiconductor device with a bipolar transistor, by which method consecutively: a surface (9) of a silicon body (1, 2) is provided with a first layer of silicon oxide (20) by means of oxidation, a base zone (21) is formed by means of ion implantation, a second layer of silicon oxide (22) is formed on the first layer of silicon oxide by means of deposition, a window (26) is formed in the two layers of silicon oxide, within which window the surface of the silicon body is exposed, a layer of polycrystalline silicon (28) is deposited on the second layer of silicon oxide and in the window, and an emitter zone (29) is formed in the base zone through diffusion of a dopant from the layer of polycrystalline silicon. A protective top layer (23) which is resistant to a cleaning bath containing HF is provided on the second layer of silicon oxide before the layer of polycrystalline silicon is deposited. Thus a usual HF dip can be carried out before the layer of polycrystalline silicon is deposited, without the bipolar transistors in an integrated circuit exhibiting strongly differing electrical properties as a result of this.