Abstract: The present disclosure provides a semiconductor structure. The semiconductor structure includes a gallium nitride (GaN) layer on a substrate; an aluminum gallium nitride (AlGaN) layer disposed on the GaN layer; a gate stack disposed on the AlGaN layer; a source feature and a drain feature disposed on the AlGaN layer and interposed by the gate stack; a dielectric material layer is disposed on the gate stack; and a field plate disposed on the dielectric material layer and electrically connected to the source feature, wherein the field plate includes a step-wise structure.

Abstract: An epitaxial substrate and a method for forming the same are disclosed. The epitaxial substrate includes a substrate, a deposition layer, a buffer layer and an epitaxial layer. The deposition layer is directly formed on the substrate, wherein the deposition layer includes a gradient doping concentration, and has a first surface and a second surface which are opposite to each other; the gradient doping concentration has a minimum value at the first surface. The buffer layer is formed on the deposition layer, and an epitaxial layer is formed on the buffer layer. The epitaxial layer is mainly formed of group III-V nitride. The substrate and the deposition layer are formed of homogeneous material. Since the deposition layer is directly formed on the substrate, and the deposition layer and the substrate are formed of a homogeneous material, the epitaxial substrate includes a good heat dissipation efficiency and low leakage current.

Abstract: An epitaxial substrate and a method for forming the same are disclosed. The epitaxial substrate includes a substrate, a deposition layer, a buffer layer and an epitaxial layer. The deposition layer is directly formed on the substrate, wherein the deposition layer includes a gradient doping concentration, and has a first surface and a second surface which are opposite to each other; the gradient doping concentration has a minimum value at the first surface. The buffer layer is formed on the deposition layer, and an epitaxial layer is formed on the buffer layer. The epitaxial layer is mainly formed of group III-V nitride. The substrate and the deposition layer are formed of homogeneous material. Since the deposition layer is directly formed on the substrate, and the deposition layer and the substrate are formed of a homogeneous material, the epitaxial substrate includes a good heat dissipation efficiency and low leakage current.

Abstract: This disclosure provides an epitaxial wafer, which includes: a silicon wafer having a central area and an extremity area enclosing the central area, the extremity area having a stepped profile; and an nitride epitaxial layer formed on the silicon wafer; wherein, the stepped profile has a width between 10 and 1500 ?m and a height between 1 and 500 ?m.

Abstract: A III-nitride based semiconductor structure includes a substrate; a buffer layer disposed above the substrate; a first gallium nitrite (GaN) layer disposed above the buffer layer and including p-type GaN; a second GaN layer disposed on the first GaN layer and including at least a first region and a second region; a channel layer disposed above the second GaN layer; a barrier layer disposed above the channel layer; and a gate electrode disposed above the barrier layer. The first region of the second GaN layer is positioned correspondingly to the gate electrode and includes n-type GaN having a first doping concentration. The second region of the second GaN layer (such as the lateral portion of the second GaN layer) is positioned correspondingly to the areas outsides the gate electrode and includes n-type GaN having a second doping concentration larger than the first doping concentration.

Abstract: A radio frequency (RF) power transistor includes a semiconductor heterostructure, a gate electrode, a drain electrode and a source electrode. The drain electrode includes an ohmic contact and a Schottky contact extending from the ohmic contact toward the gate electrode, spaced apart from the gate electrode (4) by a distance (LGD), and having a length (LEXT) being not less than 2 ?m and not greater than 4 ?m. A ratio of the length (LEXT) to a sum of the length (LEXT) and a distance (LGD) is greater than 0.83 and less than 0.98.

Abstract: A radio frequency (RF) power transistor includes a semiconductor heterostructure, a gate electrode, a drain electrode and a source electrode. The drain electrode includes an ohmic contact and a Schottky contact extending from the ohmic contact toward the gate electrode, spaced apart from the gate electrode (4) by a distance (LGD), and having a length (LEXT) being not less than 2 ?m and not greater than 4 ?m. A ratio of the length (LEXT) to a sum of the length (LEXT) and a distance (LGD) is greater than 0.83 and less than 0.98.

Abstract: A radio frequency (RF) power transistor includes: a semiconductor heterostructure that includes an undoped barrier layer and an active layer and that is formed with a continuous two dimensional electron gas (2DEG) channel having an ohmic source-aligned region, an ohmic drain-aligned region and a Schottky-aligned region; agate electrode; and source and drain electrodes. One of the source and drain electrodes includes an ohmic contact and a Schottky contact that extends from the ohmic contact toward the gate electrode. The 2DEG channel is normally on and extends continuously from the ohmic source-aligned region to the ohmic drain-aligned region. The Schottky contact overlaps and is capacitively coupled to the Schottky-aligned region of the 2DEG channel.