Integrated circuitry comprising transistor structures with a source/drain etch stop layer to limit the depth of source and drain material relative to a channel of the transistor. A portion of a channel material layer may be etched in preparation for source and drain materials. The etch may be stopped at an etch stop layer buried between a channel material layer and an underlying planar substrate layer. The etch stop layer may have a different composition than the channel layer while retaining crystallinity of the channel layer. The source and drain etch stop layer may provide adequate etch selectivity to ensure a source and drain etch process does not punch through the etch stop layer. Following the etch process, source and drain materials may be formed, for example with an epitaxial growth process. The source and drain etch stop layer may be, for example, primarily silicon and carbon.

A semiconductor device includes: a substrate; a channel layer disposed on the substrate, wherein the channel layer is made of GaN; a barrier layer disposed on the channel layer, wherein the barrier layer is made of Al.sub.zGa.sub.1-zN; and an inserting structure inserted between the channel layer and the barrier layer. The inserting structure includes: a first inserting layer disposed on the channel layer, wherein the first inserting layer is made of Al.sub.xGa.sub.1-xN; and a second inserting layer disposed on the first inserting layer, wherein the second inserting layer is made of Al.sub.yGa.sub.1-yN, and y is greater than x. The semiconductor device further includes: a gate electrode disposed on the barrier layer; a source electrode and a drain electrode disposed on the barrier layer and respectively at opposite sides of the gate electrode; and a spike region formed below at least one of the source electrode and the drain electrode.

An integrated circuit comprises a substrate that includes a first surface and a second surface. A first through substrate via (TSV) is formed between the first surface and the second surface and a first conductive material is arranged within the first TSV to form a conductive path between the first surface and the second surface through the substrate. A second TSV is formed between the first surface and the second surface and a second conductive material arranged within the second TSV to form a conductive path between the first surface and the second surface through the substrate. In examples the first TSV has a larger cross-sectional area than the second TSV, the cross-section of the first TSV and second TSV being in a plane parallel to the first surface or the second surface.

RF transistor amplifiers include an RF transistor amplifier die having a Group III nitride-based semiconductor layer structure and a plurality of gate terminals, a plurality of drain terminals, and at least one source terminal that are each on an upper surface of the semiconductor layer structure, an interconnect structure on an upper surface of the RF transistor amplifier die, and a coupling element between the RF transistor amplifier die and the interconnect structure that electrically connects the gate terminals, the drain terminals and the source terminal to the interconnect structure.

A method for forming a semiconductor transistor device includes forming a channel structure, a gate structure, a first source/drain epitaxial structure, a second source/drain epitaxial structure, a gate contact, and a back-side source/drain contact. The channel structure is formed by forming a stack of semiconductor layers. The gate structure is formed wrapping around the channel structure. The first source/drain epitaxial structure and the second source/drain epitaxial structure are formed on opposite endings of the channel structure. The gate contact is formed on the gate structure. The back-side source/drain contact is formed under the first source/drain epitaxial structure. The second source/drain epitaxial structure is formed to have a concave bottom surface.

A semiconductor structure includes an epitaxial region having a front side and a backside. The semiconductor structure includes an amorphous layer formed over the backside of the epitaxial region, wherein the amorphous layer includes silicon. The semiconductor structure includes a first silicide layer formed over the amorphous layer. The semiconductor structure includes a first metal contact formed over the first silicide layer.

A semiconductor device that comprises a substrate with a primary surface and a secondary surface opposite to the primary surface. The primary surface provides a semiconductor active device. The semiconductor device includes a base metal layer deposited on the secondary surface and within the substrate via in which a vacancy is formed, and an additional metal layer on the base metal layer, the additional metal layer having different wettability against a solder as compared to the base metal layer whereby the solder is contactable by the base metal layer and repelled by the additional metal layer. The semiconductor device is die-bonded on the assembly substrate by interposing the solder between the secondary surface and the assembly substrate. The base metal layer in a portion that excepts the substrate via and a periphery of the substrate via by partly removing the additional metal layer is in contact with the solder.

A method of forming a high electron mobility transistor (HEMT) includes: providing a semiconductor structure comprising a channel layer and a barrier layer sequentially stacked on a substrate; forming a first insulating layer on the barrier layer; and forming a gate contact, a source contact, and a drain contact on the barrier layer. An interface between the first insulating layer and the barrier layer comprises a modified interface region on a drain access region and/or a source access region of the semiconductor structure such that a sheet resistance of the drain access region and/or the source access region is between 300 and 400 Ω/sq.

A semiconductor device includes a substrate having a first surface and a second surface, the second surface being opposite to the first surface, the substrate having an opening formed from the first surface toward the second surface; a semiconductor device layer having a third surface facing the second surface; and a heat transfer member disposed in the opening, the heat transfer member being configured to transfer heat generated by the semiconductor device layer to the first surface, wherein the heat transfer member includes a diamond layer and a metal layer, the diamond layer covering a bottom surface and an inner wall surface of the opening, and the metal layer being disposed on the diamond layer.

A GaN-based high electron mobility transistor (HEMT) device includes a semiconductor structure comprising a channel layer and a barrier layer sequentially stacked on a substrate, a drain contact and a source contact on the barrier layer, and a gate contact on the barrier layer between the drain contact and the source contact. A sheet resistance of a drain access region and/or a source access region of the semiconductor structure is between 300 and 400 Ω/sq.