A semiconductor structure and a manufacturing method thereof are provided in the present disclosure. The semiconductor structure includes a semiconductor substrate; a plurality of stacked structures and a plurality of isolation structures on the semiconductor substrate, wherein the stacked structures are spaced apart each other, and each of the isolation structures are located between adjacent stacked structures; each of the stacked structures comprises a nucleation layer and a first epitaxial layer from bottom to top; and a heterojunction structure on the plurality of stacked structures, wherein the heterojunction structure is distributed over an entire surface, and an air gap is formed between the heterojunction structure and each of the isolation structures.

A method for forming a high electron mobility transistor is disclosed. A substrate is provided. A channel layer is formed on the substrate. An electron supply layer is formed on the channel layer. A dielectric passivation layer is formed on the electron supply layer. A gate recess is formed into the dielectric passivation layer and the electron supply layer. A surface modification layer is conformally deposited on an interior surface of the gate recess. The surface modification layer is first subjected to the nitride treatment and is then subjected to the oxidation treatment. A P-type GaN layer is formed in the gate recess and on the surface modification layer.

Some embodiments of the present disclosure relate to a high electron mobility transistor (HEMT) which includes a heterojunction structure arranged over a semiconductor substrate. The heterojunction structure includes a binary III/V semiconductor layer is a first III-nitride material and a ternary III/V semiconductor layer arranged over the binary III/V semiconductor layer and is a second III-nitride material. Source and drain regions are arranged over the ternary III/V semiconductor layer. A gate structure is arranged over the heterojunction structure and arranged between the source and drain regions. The gate structure is a third III-nitride material. A first passivation layer directly contacts an entire sidewall surface of the gate structure and is a fourth III-nitride material. The entire sidewall surface has no dangling bond. A second passivation layer is conformally disposed along the first passivation layer, the second passivation layer has no physical contact with the gate structure.

A semiconductor device and method for forming the same. The device comprises at least a dielectric layer, a two-dimensional (2D) material layer, a gate structure, and source/drain contacts. The 2D material layer contacts the dielectric layer. The gate structure contacts the 2D material layer. The source/drain contacts are disposed above the 2D material layer and contact the gate structure. The method includes forming a structure including at least a handle wafer, a 2D material layer, a gate structure in contact with the 2D material layer, an insulating layer, and a sacrificial layer. A portion of the sacrificial layer is etched. An inter-layer dielectric is formed in contact with the insulating layer and sidewalls of the sacrificial layer. The sacrificial layer and a portion of the insulating layer are removed. Source and drain contacts are formed in contact with the portion of the 2D material layer.

Gallium nitride-based monolithic microwave integrated circuits (MMICs) can comprise aluminum-based metals. Electrical contacts for gates, sources, and drains of transistors can include aluminum-containing metallic materials. Additionally, connectors, inductors, and interconnect devices can also comprise aluminum-based metals. The gallium-based MMICs can be manufactured in complementary metal oxide semiconductor (CMOS) facilities with equipment that produces silicon-based semiconductor devices.

This disclosure provides a semiconductor epitaxial structure and a semiconductor device. The semiconductor epitaxial structure includes a channel layer, a composite barrier layer, and a doping layer. The doping layer is disposed on the composite barrier layer, the channel layer is disposed on a side of the composite barrier layer that faces away from the doping layer, the composite barrier layer includes a digital alloy barrier layer and an AlGaN barrier layer that are disposed in a laminated manner, and the digital alloy barrier layer includes one or more AlN layers. The semiconductor epitaxial structure provided in this disclosure effectively prevents Mg ions in a p-GaN layer from diffusing to the barrier layer and the channel layer to affect density and mobility of two-dimensional electronic gas and cause a problem of an increase in on resistance.

Described herein are devices and methods that utilize three-dimensional topological semimetals (including Dirac, Weyl and nodal line) that may be useful in advanced electronic devices. The Fermi level in three dimensional topological semimetals can be significantly shifted in energy when forming a heterojunction with a semiconductor or metal. This has unintended and sometimes negative consequences for device performance. Described herein are designs and methods to modify the heterostructures to either suppress Fermi level movement or to produce an intentional shift to allow for the use of these improved semimetal devices.

A high electron mobility transistor (HEMT) includes a substrate, a channel layer, a barrier layer and a passivation layer. A contact structure is disposed on the passivation layer and extends through the passivation layer and the barrier layer to directly contact the channel layer. The contact structure includes a metal layer, and the metal layer includes a metal material doped with a first additive. A weight percentage of the first additive in the metal layer is between 0% and 2%.

A semiconductor device includes a plurality of column portions including a semiconductor. The plurality of column portions each includes a source region, a drain region, and a channel formation region including a channel formed between the source region and the drain region. The semiconductor device further includes a gate electrode provided, via an insulating layer, at a side wall of the channel formation region, and also includes a first semiconductor layer provided at a side wall of the drain region. A conductive type of the first semiconductor layer differs from a conductive type of the semiconductor included in the drain region.

A transistor including a gate region penetrating into a first gallium nitride layer, wherein a second electrically-conductive layer coats at least one of the sides of said gate region.