Abstract: A method for fabricating high electron mobility transistor (HEMT) includes the steps of: forming a buffer layer on a substrate; forming a first barrier layer on the buffer layer; forming a first hard mask on the first barrier layer; removing the first hard mask and the first barrier layer to form a recess; forming a second barrier layer in the recess; and forming a p-type semiconductor layer on the second barrier layer.

Abstract: A method for fabricating high electron mobility transistor (HEMT) includes the steps of: forming a buffer layer on a substrate; forming a first barrier layer on the buffer layer; forming a first hard mask on the first barrier layer; removing the first hard mask and the first barrier layer to form a recess; forming a second barrier layer in the recess; and forming a p-type semiconductor layer on the second barrier layer.

Abstract: An enhancement mode high electron mobility transistor (HEMT) includes a group III-V semiconductor body, a group III-V barrier layer and a gate structure. The group III-V barrier layer is disposed on the group III-V semiconductor body, and the gate structure is a stacked structure disposed on the group III-V barrier layer. The gate structure includes a gate dielectric and a group III-V gate layer disposed on the gate dielectric, and the thickness of the gate dielectric is between 15 nm to 25 nm.

Abstract: An electronic device includes a metal back cover, a metal frame, and a first, second, third, and fourth radiators. The metal frame includes a discrete part and two connection parts. The connection parts are located by two sides of the discrete part, separated from the discrete part, and connected to the metal back cover. A U-shaped slot is formed between the discrete part and the metal back cover and between the discrete part and the connection parts. The first radiator is separated from the discrete part and includes a feed end. The second, third, and fourth radiators are connected to the discrete part and the metal back cover. The third radiator is located between the first and second radiators. The first radiator is located between the third and fourth radiators. The discrete part and the first, second, third, and fourth radiators form an antenna module together.

Abstract: A method for fabricating a high electron mobility transistor (HEMT) includes the steps of forming a buffer layer on a substrate, forming a barrier layer on the buffer layer, forming a p-type semiconductor layer on the barrier layer, forming a gate electrode layer on the p-type semiconductor layer, and patterning the gate electrode layer to form a gate electrode. Preferably, the gate electrode includes an inclined sidewall.

Abstract: A method for fabricating high electron mobility transistor (HEMT) includes the steps of: forming a buffer layer on a substrate; forming a first barrier layer on the buffer layer; forming a first hard mask on the first barrier layer; removing the first hard mask and the first barrier layer to form a recess; forming a second barrier layer in the recess; and forming a p-type semiconductor layer on the second barrier layer.

Abstract: A method for fabricating a high electron mobility transistor (HEMT) includes the steps of forming a buffer layer on a substrate, forming a barrier layer on the buffer layer, forming a p-type semiconductor layer on the barrier layer, forming a hole injection buffer layer (HIBL) on the p-type semiconductor layer, and forming a gate electrode on the HIBL.

Abstract: A semiconductor device includes an enhancement mode high electron mobility transistor (HEMT) with an active region and an isolation region. The HEMT includes a substrate, a group III-V body layer, a group III-V barrier layer and a recess. The group III-V body layer is disposed on the substrate. The group III-V barrier layer is disposed on the group III-V body layer in the active region and the isolation region. The recess is disposed in the group III-V barrier layer without penetrating the group III-V barrier layer in the active region.

Abstract: A method for fabricating high electron mobility transistor (HEMT) includes the steps of: forming a buffer layer on a substrate; forming a barrier layer on the buffer layer; forming a hard mask on the barrier layer; performing an implantation process through the hard mask to form a doped region in the barrier layer and the buffer layer; removing the hard mask and the barrier layer to form a first trench; forming a gate dielectric layer on the hard mask and into the first trench; forming a gate electrode on the gate dielectric layer; and forming a source electrode and a drain electrode adjacent to two sides of the gate electrode.

Abstract: A semiconductor device provided with features of depletion mode (D-mode) and enhancement mode (E-mode) GaN devices, including a substrate with a first region and a second region defined thereon, a GaN channel layer on the substrate, a AlGaN layer on the GaN channel layer, a p-GaN layer on the AlGaN layer in the first region, a Al-based passivation layer on the AlGaN layer and p-GaN layer, and gate contact openings, wherein the gate contact opening on the first region extends through the Al-based passivation layer to the top surface of p-GaN layer, the gate contact opening on the second region extends through the Al-based passivation layer to the surface of AlGaN layer, and the surfaces of p-GaN layer and AlGaN layer are both flat surfaces without recess feature.

Abstract: A high-electron mobility transistor includes a substrate, a buffer layer over the substrate, a barrier layer over the buffer layer, and a gate structure on the barrier layer. The gate structure includes a cap layer and a gate over the cap layer. The cap layer includes a gate-leakage suppressing region on its sidewall.

Abstract: A method for fabricating high electron mobility transistor (HEMT) includes the steps of: forming a first barrier layer on a substrate; forming a p-type semiconductor layer on the first barrier layer; forming a hard mask on the p-type semiconductor layer; patterning the hard mask and the p-type semiconductor layer; and forming a spacer adjacent to the hard mask and the p-type semiconductor layer.

Abstract: A method for fabricating high electron mobility transistor (HEMT) includes the steps of: forming a first barrier layer on a substrate; forming a p-type semiconductor layer on the first barrier layer; forming a hard mask on the p-type semiconductor layer; patterning the hard mask and the p-type semiconductor layer; and forming a spacer adjacent to the hard mask and the p-type semiconductor layer.

Abstract: A semiconductor device includes an enhancement mode high electron mobility transistor (HEMT) with an active region and an isolation region. The HEMT includes a substrate, a group III-V body layer, a group III-V barrier layer, a first recess, a second recess, a passivation layer, and an etch mask layer. The group III-V barrier layer includes a thinner portion, a first thicker portion and a second thicker portion in the active region, the thinner portion surrounds the first thicker portion, and the second thicker portion surrounds the thinner portion. The first recess is disposed in the group III-V barrier layer in the active region. The second recess is disposed in the group III-V barrier layer in the isolation region.

Abstract: A method for fabricating high electron mobility transistor (HEMT) includes the steps of: forming a buffer layer on a substrate; forming a barrier layer on the buffer layer; forming a hard mask on the barrier layer; performing an implantation process through the hard mask to form a doped region in the barrier layer and the buffer layer; removing the hard mask and the barrier layer to form a first trench; forming a gate dielectric layer on the hard mask and into the first trench; forming a gate electrode on the gate dielectric layer; and forming a source electrode and a drain electrode adjacent to two sides of the gate electrode.

Abstract: A method for fabricating high electron mobility transistor (HEMT) includes the steps of: forming a buffer layer on a substrate; forming a first barrier layer on the buffer layer; forming a second barrier layer on the first barrier layer; forming a first hard mask on the second barrier layer; removing the first hard mask and the second barrier layer to form a recess; and forming a p-type semiconductor layer in the recess.

Abstract: A semiconductor transistor structure with reduced contact resistance includes a substrate, a channel layer on the substrate, a barrier layer on the channel layer, a two-dimensional electron gas (2DEG) layer at an interface between the barrier layer and the channel layer, and a recess in a contact region. The recess penetrates through the barrier layer and extends into the channel layer. An Ohmic contact metal is disposed in the recess. The Ohmic contact metal is in direct contact with a vertical side surface of the barrier layer in the recess and in direct contact with an inclined side surface of the 2DEG layer and the channel layer in the recess.

Abstract: A high electron mobility transistor includes a substrate, a mesa structure disposed on the substrate, a passivation layer disposed on the mesa structure, and at least a contact structure disposed in the passivation layer and the mesa structure. The mesa structure includes a channel layer, a barrier layer on the channel layer, two opposite first edges extending along a first direction, and two opposite second edges extending along a second direction. The contact structure includes a body portion and a plurality of protruding portions. The body portion penetrates through the passivation layer. The protruding portions penetrate through the barrier layer and a portion of the channel layer. In a top view, the body portion overlaps the two opposite first edges of the mesa structure without overlapping the two opposite second edges of the mesa structure.

Abstract: A method for fabricating high electron mobility transistor (HEMT) includes the steps of: forming a first barrier layer on a substrate; forming a p-type semiconductor layer on the first barrier layer; forming a hard mask on the p-type semiconductor layer; patterning the hard mask and the p-type semiconductor layer; and forming a spacer adjacent to the hard mask and the p-type semiconductor layer.

Abstract: A semiconductor device includes an enhancement mode high electron mobility transistor (HEMT) with an active region and an isolation region. The HEMT includes a substrate, a group III-V body layer, a group III-V barrier layer, a group III-V gate structure and a group III-V patterned structure. The group III-V body layer and the group III-V barrier layer are disposed on the substrate. The group III-V gate structure is disposed on the group III-V barrier layer within the active region. The group III-V patterned structure is disposed on the group III-V barrier layer within the isolation region. The composition of the group III-V patterned structure is the same as the composition of the group III-V gate structure.