Abstract: A high-frequency bipolar transistor structure includes a base region of a first conductivity type formed in a silicon layer of a second conductivity type, the base region comprising an intrinsic base region surrounded by an extrinsic base region, an emitter region of the second conductivity type formed inside the intrinsic base region, the extrinsic base region and the emitter region being contacted by a first polysilicon layer and a second polysilicon layer respectively. The first and the second polysilicon layers are respectively contacted by a base metal electrode and an emitter metal electrode. Between the extrinsic base region and the first polysilicon layer, a silicide layer is provided to reduce the extrinsic base resistance of the bipolar transistor.

Abstract: In a method of fabricating a self-aligned bipolar junction transistor with silicide extrinsic base contacts and selective epitaxial grown intrinsic base region, the sinker and buried N+ layer regions are formed in a semiconductor substrate with trench oxide isolation. Thin oxide is then formed on the structure. Next, metal silicide is deposited on the thin oxide and p-dopant implanted into the silicide. LTO is then deposited on the doped silicide followed by deposition of nitride. Next, the nitride, LTO and silicide layers are etched, stopping on the thin oxide layer. The thin oxide is then etched to expose the silicon. The etch undercuts the thin oxide under the nitride. A thin p+ epitaxial base is then selectively grown on the silicon and the metal silicide only. The base can be silicon or a silicon germanium layer to form a heterojunction transistor. Next, thin LTO is deposited followed by deposition of nitride. An RIE of the nitride is then performed to form nitride spacers, stopping on the thin LTO.

Abstract: Methods which provide for the formation of the intrinsic base regions and the link-up regions in separate processing steps are provided. These methods include the steps of forming a first conductive layer on a substrate of a first conductivity type containing a region of a second conductivity type therein, wherein the first conductive layer is formed on the region of second conductivity type semiconductor material. The first conductive layer is patterned to define a sidewall of a window which exposes a portion of the region of a second conductivity type semiconductor material. An insulating layer is formed on the sidewall, the first conductive layer and the exposed portion of the region of second conductivity type semiconductor material. A first mask is then formed on the insulating layer which exposes a region of the insulating layer corresponding to a link-up region of the bipolar transistor.

Abstract: A bipolar transistor (100) and a method for forming the same. A base-link diffusion source layer (118) is formed over a portion of the collector region (102). The base-link diffusion source layer (118) comprises a material that is capable of being used as a dopant source and is capable of being etched selectively with respect to silicon. A base electrode (114) is formed over at least one end portion of the base-link diffusion source layer (118) and the exposed portions of the base-link diffusion source layer (118) are removed. An extrinsic base region (110) is diffused from the base electrode (114) and a base link-up region (112) is diffused from the base-link diffusion source layer (118). Processing may then continue to form an intrinsic base region (108), emitter region (126), and emitter electrode (124).