Complementary high-voltage bipolar transistors formed in standard bulk silicon integrated circuits are disclosed. In one disclosed embodiment, collector regions are formed in an epitaxial silicon layer. Base regions and emitters are disposed over the collector region. An n-type region is formed under collector region by implanting donor impurities into a p-substrate for the PNP transistor and implanting acceptor impurities into the p-substrate for the NPN transistor prior to depositing the collector epitaxial regions. Later in the process flow these n-type and p-type regions are connected to the top of the die by a deep n+ and p+ wells respectively. The n-type well is then coupled to VCC while the p-type well is coupled to GND, providing laterally depleted portions of the PNP and NPN collector regions and hence, increasing their BVs.

This disclosure relates to bipolar transistors, such as heterojunction bipolar transistors, having at least one grading in the collector. One aspect of this disclosure is a bipolar transistor that includes a collector having a high doping concentration at a junction with the base and at least one grading in which doping concentration increases away from the base. In some embodiments, the high doping concentration can be at least about 3×10.sup.16 cm.sup.−3. According to certain embodiments, the collector includes two gradings. Such bipolar transistors can be implemented, for example, in power amplifiers.

An integrated circuit includes one or more bipolar transistors, each including a first dielectric layer located over a semiconductor layer having a first conductivity type, the dielectric layer including an opening. A second dielectric layer is located between the first dielectric layer and the semiconductor layer. The second dielectric layer defines a first recess between the first dielectric layer and the semiconductor substrate at a first side of the opening, and a second recess between the first dielectric layer and the semiconductor substrate at a second opposite side of the opening. A first doped region of the semiconductor layer is located under the opening, the first doped region having a different second conductivity type and a first width. A second doped region of the semiconductor layer is also under the opening, the second doped region having the second conductivity type and underlying the first recess and the second recess.

The present disclosure relates to semiconductor structures and, more particularly, to heterojunction bipolar transistors and methods of manufacture. The structure includes: a sub-collector region in a substrate; a collector region above the sub-collector region, the collector region composed of semiconductor material; an intrinsic base region composed of intrinsic base material surrounded by the semiconductor material above the collector region; and an emitter region above the intrinsic base region.

A method for fabricating a heterojunction bipolar transistor (HBT) comprises providing a semiconductor support layer and forming an even number of at least four elongated wall structures on the support layer. The wall structures are arranged side-by-side at a regular interval. An odd number of at least three semiconductor collector-material ridge structures are formed on the support layer. Each ridge structure is formed between two adjacent wall structures. A semiconductor base-material layer is formed on a determined ridge structure of the at least three ridge structures. A semiconductor emitter-material layer is formed on the base-material layer. The base-material layer is epitaxially extended so that it coherently covers all the wall structures and all the ridge structures. All the ridge structures except for the determined ridge structure are selectively removed.

The present disclosure relates to semiconductor structures and, more particularly, to heterojunction bipolar transistors (HBTs) with a buried trap rich region and methods of manufacture. The structure includes: a trap rich isolation region embedded within the bulk substrate; and a heterojunction bipolar transistor above the trap rich isolation region, with its sub-collector region separated by the trap rich isolation region by a layer of the bulk substrate.

The present disclosure relates to semiconductor structures and, more particularly, to heterojunction bipolar transistors (HBTs) with a buried trap rich region and methods of manufacture. The structure includes: a trap rich isolation region embedded within the bulk substrate; and a heterojunction bipolar transistor above the trap rich isolation region, with its sub-collector region separated by the trap rich isolation region by a layer of the bulk substrate.

A bipolar transistor includes a collector layer, a base layer, and an emitter layer that are formed in this order on a compound semiconductor substrate. The emitter layer is disposed inside an edge of the base layer in plan view. A base electrode is disposed on partial regions of the emitter layer and the base layer so as to extend from an inside of the emitter layer to an outside of the base layer in plan view. An insulating film is disposed between the base electrode and a portion of the base layer, with the portion not overlapping the emitter layer. An alloy layer extends from the base electrode through the emitter layer in a thickness direction and reaches the base layer. The alloy layer contains at least one element constituting the base electrode and elements constituting the emitter layer and the base layer.

The present disclosure relates to semiconductor structures and, more particularly, to heterojunction bipolar transistors (HBTs) with a buried trap rich region and methods of manufacture. The structure includes: a trap rich isolation region embedded within the bulk substrate; and a heterojunction bipolar transistor above the trap rich isolation region, with its sub-collector region separated by the trap rich isolation region by a layer of the bulk substrate.

The present disclosure relates to semiconductor structures and, more particularly, to heterojunction bipolar transistors and methods of manufacture. The structure includes a collector region composed of semiconductor material; at least one marker layer over the collector region; a layer of doped semiconductor material which forms an extrinsic base and which is located above the at least one marker layer; a cavity formed in the layer of doped semiconductor material and extending at least to the at least one marker layer; an epitaxial intrinsic base layer of doped material located within the cavity; and an emitter material over the epitaxial intrinsic base layer and within an opening formed by sidewall spacer structures.