A field effect transistor, comprising a gate contact and gate metal forming a vertical structure, such vertical structure having sides and a top surrounded by an air gap formed between a source electrode and a drain electrode of the field effect transistor.

A semiconductor device and a manufacturing method thereof are provided. The semiconductor device includes a substrate, a first channel layer, a first barrier layer, a gate electrode and an insulating structure. The substrate has a recess, and the first channel layer, the first barrier layer, the gate electrode and the insulating structure are disposed in the recess. The first channel layer covers a surface of the recess. The first barrier layer is disposed on a surface of the first channel layer. A surface of a bottom portion of the first barrier layer is covered by the gate electrode, and a top surface of the gate electrode is lower than a topmost surface of the substrate. Surfaces of the gate electrode and a top portion of the first barrier layer are covered by the insulating structure.

Embodiments of the present application disclose a semiconductor structure and a manufacturing method for the semiconductor structure, which solve problems of complicated manufacturing process and poor stability and reliability of existing semiconductor structures. The semiconductor structure includes: a substrate; a channel layer and a barrier layer sequentially superimposed on the substrate, wherein the channel layer and the barrier layer are made of GaN-based materials and an upper surface of the barrier layer is Ga-face; and a p-type GaN-based semiconductor layer formed in a gate region of the barrier layer. An upper surface of the p-type GaN-based semiconductor layer is N-face.

The present invention relates to an epitaxial structure of N-face group III nitride, its active device, and its gate protection device. The epitaxial structure of N-face AlGaN/GaN comprises a silicon substrate, a buffer layer (C-doped) on the silicon substrate, an i-GaN (C-doped) layer on the buffer layer (C-doped), an i-Al.sub.yGaN buffer layer on the i-GaN (C-doped) layer, an i-GaN channel layer on the i-Al.sub.yGaN buffer layer, and an i-Al.sub.xGaN layer on the i-GaN channel layer, where x=0.10.3 and y=0.050.75. By connecting a depletion-mode (D-mode) AlGaN/GaN high electron mobility transistor (HEMT) to the gate of a p-GaN gate enhancement-mode (E-mode) AlGaN/GaN HEMT in device design, the gate of the p-GaN gate E-mode AlGaN/GaN HEMT can be protected under any gate voltage.

In some embodiments, the present disclosure relates to a high voltage device that includes a substrate comprising a first semiconductor material. A channel layer that comprises a second semiconductor material is arranged over the substrate. An active layer that comprises a third semiconductor material is arranged over the channel layer. Over the active layer is a source contact spaced apart from a drain contact. A gate structure is arranged laterally between the source and drain contacts and over the active layer to define a high electron mobility transistor (HEMT) device. Between the gate structure and the source contact is a cap structure, which is coupled to the source contact and laterally spaced from the gate structure. The cap structure and a gate electrode of the gate structure comprise a same material.

A semiconductor device includes a substrate, an active region and an inactive region surrounding the active region, a gate electrode, a drain electrode and a source electrode on the active region, a drain interconnection including a drain finger and a drain bar, and a source interconnection including a source finger and a source bar. The source bar is located on an opposite side of the drain bar across the active region in a first direction. The source electrode includes a first side facing the drain bar in the first direction and a first depression in a middle of the first side. A first depth of the first depression in the first direction is equal or more than a first interval between the drain bar and the first side in the first direction.

A process of forming a field effect transistor (FET) of a type of high electron mobility transistor (HEMT) reducing damages caused in a semiconductor layer is disclosed. The process carries out steps of: (a) depositing an insulating film on a semiconductor stack; (b) depositing a conductive film on the insulating film; (c) forming an opening in the conductive film and the insulating film by a dry-etching using ions of reactive gas to expose a surface of the semiconductor stack; and (d) forming a gate electrode to be in contact with the surface of the semiconductor stack through the opening, the gate electrode filling the opening in the conductive film and the insulating film.

The present disclosure relates to a high electron mobility transistor (HEMT) and a fabrication method thereof. The HEMT may include a substrate; a channel layer disposed on the substrate; a barrier layer disposed on the channel layer; a semiconductor gate disposed on the barrier layer; a metal gate disposed on the semiconductor gate, the metal gate having a trapezoidal cross-sectional shape; and a passivation layer directly contacting the metal gate. A first surface of the metal gate contacts a first surface of the semiconductor gate, and an edge of the first surface of the metal gate is located inside an edge of the first surface of the semiconductor gate.

Included are forming, on a semiconductor substrate, an insulation film having an opening section where an opening is formed, forming a first resist on the insulation film while avoiding the opening section and the semiconductor substrate exposed via the opening section, forming a first metal on the opening section, the semiconductor substrate exposed via the opening section, and the first resist by a vapor deposition method or a sputtering method, removing, by a lift-off method, the first resist and the first metal on the first resist, forming, on the insulation film, a second resist allowing the first metal to be exposed, causing the first metal to grow a second metal by an electroless plating method, and removing the second resist, where these processings are included in the listed order.

An object of the technique disclosed in the Description is to provide a semiconductor device that reduces a gate leakage current without degrading its high-frequency characteristic. A semiconductor device relating to the technique disclosed in the Description includes a nitride semiconductor layer, a first insulating film partly disposed on the upper surface of the nitride semiconductor layer, and a gate electrode provided to have a lower surface that is at least partly in contact with the upper surface of the nitride semiconductor layer that is exposed without being covered with the first insulating film. The first insulating film is provided to be in contact with a side surface of the gate electrode. The first insulating film contains a transition metal.