A method of fabricating a transistor includes doping non-overlapping first, second, and third wells in a silicon layer of a substrate. The substrate, second and third wells have a first type of conductivity and the first well and silicon layer have a second type of conductivity. First and second insulating layers are thermally grown over the second well between the first well and the third well, and over the third well, respectively. A gate stack is formed over the first insulating layer and the third well. A first source region having the second type of conductivity is formed in the third well. A gate spacer is formed, a fourth well having the first type of conductivity is doped in the third well between the second insulating layer and the gate spacer, a second source region is formed over the fourth well, and a drain is formed in the first well.

Techniques are disclosed for forming column IV transistor devices having source/drain regions with high concentrations of germanium, and exhibiting reduced parasitic resistance relative to conventional devices. In some example embodiments, the source/drain regions each includes a thin p-type silicon or germanium or SiGe deposition with the remainder of the source/drain material deposition being p-type germanium or a germanium alloy (e.g., germanium:tin or other suitable strain inducer, and having a germanium content of at least 80 atomic % and 20 atomic % or less other components). In some cases, evidence of strain relaxation may be observed in the germanium rich cap layer, including misfit dislocations and/or threading dislocations and/or twins. Numerous transistor configurations can be used, including both planar and non-planar transistor structures (e.g., FinFETs and nanowire transistors), as well as strained and unstrained channel structures.

Techniques are disclosed for forming column IV transistor devices having source/drain regions with high concentrations of germanium, and exhibiting reduced parasitic resistance relative to conventional devices. In some example embodiments, the source/drain regions each includes a thin p-type silicon or germanium or SiGe deposition with the remainder of the source/drain material deposition being p-type germanium or a germanium alloy (e.g., germanium:tin or other suitable strain inducer, and having a germanium content of at least 80 atomic % and 20 atomic % or less other components). In some cases, evidence of strain relaxation may be observed in the germanium rich cap layer, including misfit dislocations and/or threading dislocations and/or twins. Numerous transistor configurations can be used, including both planar and non-planar transistor structures (e.g., FinFETs and nanowire transistors), as well as strained and unstrained channel structures.

Techniques are disclosed for forming transistor devices having reduced parasitic contact resistance relative to conventional devices. The techniques can be implemented, for example, using a standard contact stack such as a series of metals on, for example, silicon or silicon germanium (SiGe) source/drain regions. In accordance with one example such embodiment, an intermediate boron doped germanium layer is provided between the source/drain and contact metals to significantly reduce contact resistance. Numerous transistor configurations and suitable fabrication processes will be apparent in light of this disclosure, including both planar and non-planar transistor structures (e.g., FinFETs), as well as strained and unstrained channel structures. Graded buffering can be used to reduce misfit dislocation. The techniques are particularly well-suited for implementing p-type devices, but can be used for n-type devices if so desired.

A digital circuit includes at least one quantum wire resonant tunneling transistor that includes an emitter terminal, a base terminal, a collector terminal, an emitter region in connection with the emitter terminal, a base region in connection with the base terminal, a collector region in connection with the collector terminal, an emitter barrier region between the emitter region and the base region, and a collector barrier region between the collector region and the base region. At least one of the emitter region, the base region, and the collector region includes a plurality of metal quantum wires.

Techniques are disclosed for forming transistor devices having source and drain regions with high concentrations of boron doped germanium. In some embodiments, an in situ boron doped germanium, or alternatively, boron doped silicon germanium capped with a heavily boron doped germanium layer, are provided using selective epitaxial deposition in the source and drain regions and their corresponding tip regions. In some such cases, germanium concentration can be, for example, in excess of 50 atomic % and up to 100 atomic %, and the boron concentration can be, for instance, in excess of 1E20 cm.sup.−3. A buffer providing graded germanium and/or boron concentrations can be used to better interface disparate layers. The concentration of boron doped in the germanium at the epi-metal interface effectively lowers parasitic resistance without degrading tip abruptness. The techniques can be embodied, for instance, in planar or non-planar transistor devices.

A semiconductor transistor device includes an emitter region that includes a plurality of metal quantum wires and is connected to an emitter terminal, a base region that includes a plurality of metal quantum wires and is connected to a base terminal, a collector region comprising a plurality of metal quantum wires and is connected to a collector terminal, an emitter barrier region between the emitter region and the base region, and a collector barrier region between the collector region and the base region.

Amorphous multi-component metallic films can be used to improve the performance of electronic devices such as resistors, diodes, and thin film transistors. An amorphous hot electron transistor (HET) having co-planar emitter and base electrodes provides electrical properties and performance advantages over existing vertical HET structures. Emitter and the base terminals of the transistor are both formed in an upper crystalline metal layer of an amorphous nonlinear resistor. The emitter and the base are adjacent to one another and spaced apart by a gap. The presence of the gap results in two-way Fowler-Nordheim tunneling between the crystalline metal layer and the amorphous metal layer, and symmetric I-V performance. Meanwhile, forming the emitter and base terminals in the same layer simplifies the HET fabrication process by reducing the number of patterning steps.

A semiconductor transistor device includes an emitter region that includes a plurality of metal quantum wires and is connected to an emitter terminal, a base region that includes a plurality of metal quantum wires and is connected to a base terminal, a collector region comprising a plurality of metal quantum wires and is connected to a collector terminal, an emitter barrier region between the emitter region and the base region, and a collector barrier region between the collector region and the base region.

Techniques are disclosed for forming column IV transistor devices having source/drain regions with high concentrations of germanium, and exhibiting reduced parasitic resistance relative to conventional devices. In some example embodiments, the source/drain regions each includes a thin p-type silicon or germanium or SiGe deposition with the remainder of the source/drain material deposition being p-type germanium or a germanium alloy (e.g., germanium:tin or other suitable strain inducer, and having a germanium content of at least 80 atomic % and 20 atomic % or less other components). In some cases, evidence of strain relaxation may be observed in the germanium rich cap layer, including misfit dislocations and/or threading dislocations and/or twins. Numerous transistor configurations can be used, including both planar and non-planar transistor structures (e.g., FinFETs and nanowire transistors), as well as strained and unstrained channel structures.