The disclosed technology generally relates to ferroelectric materials and semiconductor devices, and more particularly to semiconductor memory devices incorporating doped polar materials. In one aspect, a semiconductor device comprises a capacitor which in turn comprises a polar layer comprising a base polar material doped with a dopant. The base polar material includes one or more metal elements and one or both of oxygen or nitrogen. The dopant comprises a metal element that is different from the one or more metal elements and is present at a concentration such that a ferroelectric switching voltage of the capacitor is different from that of the capacitor having the base polar material without being doped with the dopant by more than about 100 mV. The capacitor stack additionally comprises first and second crystalline conductive oxide electrodes on opposing sides of the polar layer. The capacitor stack further comprises first and second barrier metal layers on respective ones of the first and second crystalline conductive oxide electrodes on opposing sides of the polar layer.

A semiconductor device and fabrication method are described for manufacturing a heterojunction bipolar transistor by forming a silicon collector region in a substrate which includes a lower collector layer, a dopant diffusion barrier layer, and an upper collector layer, where the formation of the dopant diffusion barrier layer reduces diffusion of dopants from the lower collector layer into the upper collector layer during one or more subsequent manufacturing steps which are used to form a trench isolation region in the substrate along with a heterogeneous base region and a silicon emitter region.

A semiconductor device and fabrication method are described for manufacturing a heterojunction bipolar transistor by forming a silicon collector region in a substrate which includes a lower collector layer, a dopant diffusion barrier layer, and an upper collector layer, where the formation of the dopant diffusion barrier layer reduces diffusion of dopants from the lower collector layer into the upper collector layer during one or more subsequent manufacturing steps which are used to form a trench isolation region in the substrate along with a heterogeneous base region and a silicon emitter region.

This disclosure relates to bipolar transistors, such as heterojunction bipolar transistors, having increased collector thickness for improved ruggedness. In some embodiments, the collector thickness can be above 1.1 microns. The collector can have at least one doping concentration grading. The collector can have a high doping concentration at a junction between the collector and the sub-collector, such as at the high end of the grading. In some embodiments, the high doping concentration can be above about 9×10.sup.16 cm.sup.−3. The collector can include a region with high doping concentration adjacent the base. The collector can include a discontinuity in the doping concentration, such as at the low end of the grading. Such bipolar transistors can be implemented, for example, in power amplifiers.

A process of fabricating semiconductor devices includes determining a correlation between band gap and long range order parameter for one or more stoichiometries. Semiconductor materials having a preselected (target) band gap can be fabricated by controlling process parameters to form a material having a stoichiometry and long range order parameter having the target band gap.

A heterojunction bipolar transistor includes: a substrate; a base mesa disposed on the substrate, wherein the base mesa includes a collector layer and a base layer disposed on the collector layer, and wherein in a top view, the base layer includes a first edge and a second edge opposite to the first edge; an emitter layer disposed on the base layer; a base electrode disposed on the substrate and connected to the base layer; a dielectric layer disposed on the base electrode, wherein a first via hole is formed in the dielectric layer at the first edge of the base layer, and a second via hole is formed in the dielectric layer at the second edge of the base layer; and a conductive feature disposed on the dielectric layer, wherein the conductive feature is connected to the base electrode through the first via hole and the second via hole.

A semiconductor device that includes a bipolar transistor, wherein a third opening, through which a pillar bump and a second wiring line, which is electrically connected to an emitter layer, contact each other, is shifted in a longitudinal direction of the emitter layer away from a position at which the third opening would be directly above the emitter layer. The third opening is arranged, with respect to the emitter layer, such that an end portion of the emitter layer in the longitudinal direction of the emitter layer and the edge of the opening of the third opening are substantially aligned with each other.

A semiconductor device that includes a bipolar transistor, wherein a third opening, through which a pillar bump and a second wiring line, which is electrically connected to an emitter layer, contact each other, is shifted in a longitudinal direction of the emitter layer away from a position at which the third opening would be directly above the emitter layer. The third opening is arranged, with respect to the emitter layer, such that an end portion of the emitter layer in the longitudinal direction of the emitter layer and the edge of the opening of the third opening are substantially aligned with each other.

A tunneling transistor is implemented in silicon, using a FinFET device architecture. The tunneling FinFET has a non-planar, vertical, structure that extends out from the surface of a doped drain formed in a silicon substrate. The vertical structure includes a lightly doped fin defined by a subtractive etch process, and a heavily-doped source formed on top of the fin by epitaxial growth. The drain and channel have similar polarity, which is opposite that of the source. A gate abuts the channel region, capacitively controlling current flow through the channel from opposite sides. Source, drain, and gate terminals are all electrically accessible via front side contacts formed after completion of the device. Fabrication of the tunneling FinFET is compatible with conventional CMOS manufacturing processes, including replacement metal gate and self-aligned contact processes. Low-power operation allows the tunneling FinFET to provide a high current density compared with conventional planar devices.

Aspects generally relate to a heterojunction bipolar transistor (HBT), and method of manufacturing the same. The HBT including an emitter a first, a first side of a base coupled to a second side of the emitter opposite the first side of the emitter. A collector coupled to the base on a second side of the base opposite the emitter, wherein an area of a junction between the base and the collector is less than or equal to an area of a junction between the base and the emitter. A dielectric coupled to the collector. A first conductive base contact coupled to the base and adjacent to the collector and extending over a base-collector junction, the conductive base contact operative as a field plate.