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: 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 gallium nitride device and a method for manufacturing a high electron mobility transistor are provided. The gallium nitride device includes a substrate, a channel layer disposed on the substrate, a barrier layer disposed on the channel layer, a cap layer disposed on the barrier layer, a gate disposed on the cap layer, a source, a drain, and ohmic sidewall dams. The source and the drain are formed in the cap layer and the barrier layer. Each of the source and the drain has a trench portion, and a contact below the trench portion and protruding into the channel layer. The ohmic sidewall dams are disposed on a sidewall of the trench portion of each of the source and the drain.

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 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 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 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 high electron mobility transistor (HEMT) and method for forming the same are disclosed. The 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 and the mesa structure. The mesa structure includes a channel layer and a barrier layer disposed on the channel layer. The contact structure includes a body portion and a plurality of protruding portions. The body portion is through the passivation layer. The protruding portions connect to a bottom surface of the body portion and through the barrier layer and a portion of the channel layer.

Abstract: The present disclosure provides a high electron mobility transistor (HEMT) including a substrate; a buffer layer over the substrate; a GaN layer over the buffer layer; a first AlGaN layer over the GaN layer; a first AlN layer over the first AlGaN layer; a p-type GaN layer over the first AlN layer; and a second AlN layer on the p-type GaN layer.

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 GaN channel layer over the substrate, an AlGaN layer over the GaN channel layer, a gate recess in the AlGaN layer, a source region and a drain region on opposite sides of the gate recess, a GaN source layer and a GaN drain layer grown on the AlGaN layer within the source region and the drain region, respectively, a p-GaN gate layer in and on the gate recess; and a re-grown AlGaN film on the AlGaN layer, on the GaN source layer and the GaN drain layer, and on interior surface of the gate recess.

Abstract: A method for forming a high-electron mobility transistor is disclosed. A substrate is provided. A buffer layer is formed over the substrate. A GaN channel layer is formed over the buffer layer. An AlGaN layer is formed over the GaN channel layer. A GaN source layer and a GaN drain layer are formed on the AlGaN layer within a source region and a drain region, respectively. A gate recess is formed in the AlGaN layer between the source region and the drain region. A p-GaN gate layer is then formed in and on the gate recess.

Abstract: A high electron mobility transistor (HEMT) includes a buffer layer on a substrate, a barrier layer on the buffer layer, a p-type semiconductor layer on the buffer layer, a gate electrode on the p-type semiconductor layer, a source electrode and a drain electrode adjacent to two sides of the gate electrode on the barrier layer, a hard mask on the barrier layer and around the p-type semiconductor layer, the source electrode, and the drain electrode, and a passivation layer on the hard mask.