Abstract: Semiconductor devices are provided. In one example, a semiconductor device includes a semiconductor structure having a buried layer at a depth of about 275 Angstroms or greater (e.g., about 500 Angstroms or greater) from a surface of the semiconductor structure. The semiconductor device includes an implanted region extending at least partially through the semiconductor structure and into the buried layer. The implanted region includes a distribution of implanted dopants of a first conductivity type extending into the buried layer. The semiconductor device includes an electrode on the implanted region. In some examples, the semiconductor structure may include an N-polar Group III-nitride semiconductor structure.

Abstract: Transistor devices are provided. In one example, the transistor device includes a channel layer. The transistor device includes a multilayer barrier structure on the channel layer. The transistor device includes a gate contact having a gate length of about 100 nm or less. A ratio of the gate length to a thickness of the multilayer barrier structure is in a range of about 8:1 to about 16:1.

Abstract: Transistor devices are provided. In one example, the transistor device includes a channel layer. The transistor device includes a multilayer barrier structure on the channel layer. The multilayer barrier structure includes a first Group III-nitride layer and a second Group III-nitride layer on the first Group III-nitride layer and opposite to the channel layer. The first Group III-nitride layer has a thickness greater than a thickness of the second Group III-nitride layer. An aluminum concentration of the first Group III-nitride layer is at least two times greater than an aluminum concentration of the second Group III-nitride layer.

Abstract: A method of forming ohmic contacts on a semiconductor layer includes forming silicon ohmic contact precursors on the semiconductor layer, depositing a layer of metal on the semiconductor layer including the silicon ohmic contact precursors, reacting the layer of metal with the silicon ohmic contact precursors to form metal silicide ohmic contacts on the semiconductor layer, and selectively removing the layer of metal from the semiconductor layer without removing the metal silicide contacts from the semiconductor layer.

Abstract: A transistor die includes a transistor including a control terminal, an output terminal, and a first partial matching circuit. The first partial matching circuit is connected to at least one of the control terminal of the transistor and the output terminal of the transistor, and is configured to tune an input impedance of the transistor die. A packaged device is also provided.

Abstract: A high electron mobility transistor comprises a semiconductor layer structure that includes a channel layer and a barrier layer and source and drain contacts on the semiconductor layer structure. A gate contact and a multi-layer passivation structure are provided on the semiconductor layer structure between the source contact and the drain contact. The multi-layer passivation structure comprises at least first and second silicon nitride layers that have different material compositions. A spacer passivation layer is provided on sidewalls of the first and second silicon nitride layers. A material composition of the spacer passivation layer is different than a material composition of at least one of the layers of the multi-layer passivation structure.

Abstract: A transistor device includes a substrate, a semiconductor structure on the substrate, a metallization layer comprising a non-planar surface on a surface of the semiconductor structure, a non-planar encapsulation layer on the non-planar surface of the metallization layer, the non-planar encapsulation layer comprising a non-planar encapsulant surface that is opposite the non-planar surface, and a self-planarizing encapsulation layer on the non-planar encapsulation layer and comprising a planarized surface that is opposite the non-planar encapsulant surface.

Abstract: A transistor device includes a semiconductor structure comprising a channel layer and a barrier layer, source and drain contacts on the semiconductor structure, and a conductive element in a recess in the barrier layer between the source and drain contacts. The barrier layer has a first thickness adjacent the source or drain contact, a second thickness at a floor of the recess between the conductive element and the channel layer, and the first thickness is about 1.2 times to 4 times greater than the second thickness. Related methods of fabrication using a looped recess process are also discussed.

Abstract: A transistor device includes a semiconductor structure comprising a channel layer and a barrier layer; source and drain contacts on the semiconductor structure; and a gate on the semiconductor structure between the source and drain contacts. A first portion of the barrier layer extending between the source or drain contact and the gate has a first thickness, a second portion of the barrier layer between the gate and the channel layer has a second thickness, and the first thickness is about 1.5 times to 4 times greater than the second thickness. Related methods of fabrication using a looped recess process are also discussed.

Abstract: A gallium nitride-based RF transistor amplifier comprises a semiconductor layer structure comprising a barrier layer on a channel layer, first and second source/drain regions in the semiconductor layer structure, first and second source/drain contacts on the respective first and second source/drain regions, and a longitudinally-extending gate finger that is between the first and second source/drain contacts. The first and second source/drain contacts each has an inner sidewall that faces the gate finger and an opposed outer sidewall. The first source/drain region extends a first distance from a lower edge of the inner sidewall of the first source/drain contact towards the second source/drain region along a transverse axis that extends parallel to a plane defined by the upper surface of the semiconductor layer structure, and extends a second, smaller distance from a lower edge of the outer sidewall of the first source/drain contact away from the second source/drain region.

Abstract: A transistor device includes a semiconductor layer, source and drain contacts on the semiconductor layer, a gate contact on the semiconductor layer between the source and drain contacts, and a field plate over the semiconductor layer between the gate contact and the drain contact. The transistor device includes a first electrical connection between the field plate and the source contact that is outside an active region of the transistor device, and a second electrical connection between the field plate and the source contact.

Abstract: A HEMT transistor has a semiconductor layer structure that comprises a Group III nitride-based channel layer and a higher bandgap Group III nitride-based barrier layer on the channel layer. A gate finger and first and second source/drain contacts are provided on the semiconductor layer structure. A first source/drain region is provided in the semiconductor layer structure that includes a first implanted region that is underneath the first source/drain contact and a first auxiliary implanted region. A depth of the first implanted region is at least twice a depth of the first auxiliary implanted a region. The first source/drain region extends inwardly a first distance from a lower edge of an inner sidewall of the first source/drain contact, and extends outwardly a second smaller distance from a lower edge of an outer sidewall of the first source/drain contact.

Abstract: A packaged electronic circuit includes a substrate having an upper surface, a first metal layer on the upper surface of the substrate, a first polymer layer on the first metal layer opposite the substrate, a second metal layer on the first polymer layer opposite the first metal layer, a dielectric layer on the first polymer layer and at least a portion of the second metal layer and a second polymer layer on the dielectric layer.

Abstract: A transistor device includes a semiconductor epitaxial layer structure including a channel layer and a barrier layer on the channel layer, a source contact and a drain contact on the barrier layer, an insulating layer on the semiconductor layer between the source contact and the drain contact, and a gate contact on the insulating layer. The gate contact includes a central portion that extends through the insulating layer and contacts the barrier layer and a drain side wing that extends laterally from the central portion of the gate toward the drain contact by a distance ?D. The drain side wing of the gate contact is spaced apart from the barrier layer by a distance d1 that is equal to a thickness of the insulating layer. The distance ?D is less than about 0.3 ?m, and the distance d1 is less than about 80 nm.

Abstract: A transistor includes a semiconductor layer and a channel region. The transistor further includes a first doped contact region in the semiconductor layer and adjacent the channel region. The transistor further includes a first ohmic contact including an interface region comprising a first interface length between the first ohmic contact and the first doped contact region larger than a length of the interface region.

Abstract: A power amplifier comprising a GaN-based high electron mobility transistor (HEMT) device, wherein a power added efficiency (PAE) of the power amplifier is greater than 32% at P1DB during operation of the power amplifier between 26.5 GHz and 30.5 GHz.

Abstract: A semiconductor device includes a substrate having an upper surface including a recess region, a semiconductor structure on the substrate, a portion of the semiconductor structure within the recess region, and a gate contact, a drain contact, and a source contact on the semiconductor structure. The recess region does not vertically overlap the drain contact or the source contact.

Abstract: A transistor device includes a substrate, a semiconductor structure on the substrate, a metallization layer comprising a non-planar surface on a surface of the semiconductor structure, a non-planar encapsulation layer on the non-planar surface of the metallization layer, the non-planar encapsulation layer comprising a non-planar encapsulant surface that is opposite the non-planar surface, and a self-planarizing encapsulation layer on the non-planar encapsulation layer and comprising a planarized surface that is opposite the non-planar encapsulant surface.

Abstract: A semiconductor die includes a semiconductor body having a gate, a source contact, and a drain contact thereon, a metal contact structure on the semiconductor body and electrically connected to the gate, the source contact, or the drain contact, and an encapsulation structure. The encapsulation structure includes first and second encapsulation layers of respective non-conductive materials stacked on the metal contact structure, and an opening extending therethrough to expose the metal contact structure. The opening includes a sidewall having a substantially continuous slope that extends through the first and second encapsulation layers to the metal contact structure. Related devices and fabrication methods are also discussed.

Abstract: A transistor device includes a semiconductor structure, source and drain contacts on the semiconductor structure, a gate on the semiconductor structure between the source and drain contacts, and a surface passivation layer on the semiconductor structure between the gate and the source or drain contact. The surface passivation layer includes an opening therein that exposes a first region of the semiconductor structure for processing the first region differently than a second region of the semiconductor structure adjacent the gate. Related devices and fabrication methods are also discussed.