A semiconductor device is provided that includes a first of a source region and a drain region comprised of a first semiconductor material, wherein an etch stop layer of a second semiconductor material present within the first of the source region and the drain region. A channel semiconductor material is present atop the first of the source region and the drain region. A second of the source and the drain region is present atop the channel semiconductor material. The semiconductor device may be a vertically orientated fin field effect transistor or a vertically orientated tunnel field effect transistor.

A method to form a semiconductor structure with an active region and a compatible dielectric layer is described. In one embodiment, a semiconductor structure has a dielectric layer comprised of an oxide of a first semiconductor material, wherein a second (and compositionally different) semiconductor material is formed between the dielectric layer and the first semiconductor material. In another embodiment, a portion of the second semiconductor material is replaced with a third semiconductor material in order to impart uniaxial strain to the lattice structure of the second semiconductor material.

One aspect of this disclosure is a power amplifier module that includes a power amplifier configured to provide a radio frequency signal at an output, an output matching network coupled to the output of the power amplifier and configured to provide impedance matching at a fundamental frequency of the radio frequency signal, and a harmonic termination circuit coupled to the output of the power amplifier. The power amplifier is included on a power amplifier die. The output matching network can include a first circuit element electrically connected to an output of the power amplifier by way of a pad on a top surface of a conductive trace, in which the top surface has an unplated portion between the pad the power amplifier die. The harmonic termination circuit can include a second circuit element. The first and second circuit elements can have separate electrical connections to the power amplifier die. Other embodiments of the module are provided along with related methods and components thereof.

A method of fabricating a multi-layer epitaxial buffer layer stack for transistors includes depositing a buffer stack on a substrate. A first voided Group IIIA-N layer is deposited on the substrate, and a first essentially void-free Group IIIA-N layer is then deposited on the first voided Group IIIA-N layer. A first high roughness Group IIIA-N layer is deposited on the first essentially void-free Group IIIA-N layer, and a first essentially smooth Group IIIA-N layer is deposited on the first high roughness Group IIIA-N layer. At least one Group IIIA-N surface layer is then deposited on the first essentially smooth Group IIIA-N layer.

In an embodiment, a semiconductor device includes a Group III-nitride-based High Electron Mobility Transistor (HEMT) configured as a bidirectional switch. The Group III nitride-based HEMT includes a first input/output electrode, a second input/output electrode, a gate structure arranged between the first input/output electrode and the second input/output electrode, and a field plate structure.

This disclosure relates to methods of forming bipolar transistors, such as heterojunction bipolar transistors. The methods may include forming a sub-collector over a substrate, forming a first portion of a collector over the sub-collector and doping a second portion of the collector to form a doping spike. The method may further include forming a third portion of the collector over the doping spike and forming a base of the bipolar transistor over the third portion of the collector.

An electronic device can include a HEMT including at least two channel layers. In an embodiment, a lower semiconductor layer overlies a lower channel layer, wherein the lower semiconductor layer has an aluminum content that is at least 10% of a total metal content of the lower semiconductor layer. An upper semiconductor layer overlies the upper channel layer, wherein the upper semiconductor layer has an aluminum content that is greater as compared to the lower semiconductor layer. In another embodiment, an electronic device can include stepped source and drain electrodes, so that lower contact resistance can be achieved. In a further embodiment, an absolute value of a difference between pinch-off or threshold voltages between different channel layers is greater than 1 V and allows current to be turned on or turned off for a channel layer without affecting another channel layer.

After forming a sacrificial gate structure straddling a stacking of a semiconductor mandrel structure and a dielectric mandrel cap and spacers present on sidewalls of the stack, portions of the spacers located on opposite sides of the sacrificial gate structure are removed. Epitaxial source/drain regions are formed on exposed sidewalls of portions of the semiconductor mandrel structure located on opposite sides of the sacrificial gate structure. The sacrificial gate structure is removed to provide a gate cavity. Next, portions of the spacers exposed by the gate cavity are removed to expose sidewalls of a portion of the semiconductor mandrel structure. III-V compound semiconductor channel portions are then formed on exposed sidewalls of the semiconductor mandrel structure. Portions of the semiconductor mandrel structure and the dielectric mandrel cap exposed by the gate cavity are subsequently removed from the structure, leaving only the III-V compound semiconductor channel portions.

A lattice matched epitaxial oxide interlayer is disposed between each semiconductor layer of a graded buffer layer material stack. Each lattice matched epitaxial oxide interlayer inhibits propagation of threading dislocations from one semiconductor layer of the graded buffer layer material stack into an overlying semiconductor layer of the graded buffer layer material stack. This allows for decreasing the thickness of each semiconductor layer within the graded buffer layer material stack. The topmost semiconductor layer of the graded buffer layer material stack, which is a relaxed layer, contains a lower defect density than the other semiconductor layers of the graded buffer layer material stack.

Techniques related to III-N transistors having self aligned gates, systems incorporating such transistors, and methods for forming them are discussed. Such transistors include a polarization layer between a raised source and a raised drain, a gate between the source and drain and over the polarization layer, and lateral epitaxial overgrowths over the source and drain and having and opening therebetween such that at least a portion of the gate adjacent to the polarization layer is aligned with the opening.