In one example, a sensor includes a heterojunction bipolar transistor and component sensing surface coupled to the heterojunction bipolar transistor via an extended base component. In another example, a biosensor for detecting a target analyte includes a heterojunction bipolar transistor and a sensing surface. The heterojunction bipolar transistor includes a semiconductor emitter including an emitter electrode for connecting to an emitter voltage, a semiconductor collector including a collector electrode for connecting to a collector voltage, and a semiconductor base positioned between the semiconductor emitter and the semiconductor collector. The sensing surface is coupled to the semiconductor base of the heterojunction bipolar transistor via an extended base component and includes a conducting film and a reference electrode.

Aspects of the disclosure provide an integrated circuit (IC) structure with a bipolar transistor stack within a substrate. The bipolar transistor stack may include: a collector, a base on the collector, and an emitter on a first portion of the base. A horizontal width of the emitter is less than a horizontal width of the base, and an upper surface of the emitter is substantially coplanar with an upper surface of the substrate. An extrinsic base structure is on a second portion of the base of the bipolar transistor stack, and horizontally adjacent the emitter. The extrinsic base structure includes an upper surface above the upper surface of the substrate.

A bipolar transistor includes a stack of an emitter, a base, and a collector. The base is structured to have a comb shape including fingers oriented in a plane orthogonal to a stacking direction of the stack.

Power is inverted using double-base-contact bidirectional bipolar transistors in a three-level-inverter topology. The transistors not only switch to synthesize a PWM approximation of the desired AC waveform, but also have transient phases of diode conduction before each full turn-on or turn-off.

Device structure and fabrication methods for a bipolar junction transistor. An emitter layer is formed on a base layer and etched to form an emitter of the device structure. The emitter layer has a concentration of an element that varies as a function of the thickness of the emitter layer. The etch rate of the emitter layer varies as a function of the concentration of the element such that the emitter has a variable width over the thickness of the emitter layer.

A bi-directional bipolar junction transistor (BJT) structure, comprising: a base region of a first conductivity type, wherein said base region constitutes a drift region of said structure; first and second collector/emitter (CE) regions, each of a second conductivity type adjacent opposite ends of said base region; wherein said base region is lightly doped relative to said collector/emitter regions; the structure further comprising: a base connection to said base region, wherein said base connection is within or adjacent to said first collector/emitter region.

A semiconductor device includes: a drift layer; a base layer on the drift layer; a collector layer and a cathode layer opposite to the base layer; multiple trenches penetrating the base layer; a gate electrode in each trench; an emitter region in a surface portion of the base layer and contacting each trench; a first electrode connected to the base layer and the emitter region; and a second electrode connected to the collector layer and the cathode layer. The gate electrodes in a diode region of a semiconductor substrate are controlled independently from the gate electrodes in the IGBT region. A voltage not forming an inversion layer in the base layer is applied to the gate electrodes in the diode region.

A semiconductor device includes: an FET structure that is formed next to a looped trench on a semiconductor substrate and that has an n.sup.+ emitter region and an n.sup.− drain region facing each other in the depth direction of the looped trench across a p-type base region; a p-type floating region formed on the side of the looped trench opposite to the FET structure; and an emitter connecting part that is electrically connected to the n.sup.+ emitter region and a trench gate provided in the same trench, the emitter connecting part and the trench gate being insulated from each other by the looped trench. The trench gate faces the FET structure, and the emitter connecting part faces the p-type floating region, across an insulating film.

A bipolar transistor is supported by a substrate including a semiconductor layer overlying an insulating layer. A transistor base is formed by a base region in the semiconductor layer that is doped with a first conductivity type dopant at a first dopant concentration. The transistor emitter and collector are formed by regions doped with a second conductivity type dopant and located adjacent opposite sides of the base region. An extrinsic base includes an epitaxial semiconductor layer in contact with a top surface of the base region. The epitaxial semiconductor layer is doped with the first conductivity type dopant at a second dopant concentration greater than the first dopant concentration. Sidewall spacers on each side of the extrinsic base include an oxide liner on a side of the epitaxial semiconductor layer and the top surface of the base region.

An RB-IGBT is provided that has a new emitter trench structure with improved breakdown voltage achieved by improving the electrical field distribution of the drift region. The RB-IGBT includes an isolation region having a first conductivity type on a side surface of a semiconductor substrate. The semiconductor substrate includes a drift region having a second conductivity type; a collector region having the first conductivity type and provided farther downward than the drift region; and an emitter trench portion provided extending to the drift region in a thickness direction from a front surface to a back surface of the semiconductor substrate. The emitter trench portion includes a trench electrode electrically connected to an emitter electrode provided above the semiconductor substrate; an upper trench insulating film directly contacting a bottom portion and side portions of the trench electrode; and a lower trench insulating film provided below the upper trench insulating film.