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 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 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 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: 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 (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: A substrate is provided having an oxide layer, a first nitride-silicon, a STI, and a second nitride-silicon. A pattern poly-silicon layer on the second nitride-silicon layer is etched to form a deep trench opening. Etching the pattern poly-silicon layer also deepens the deep trench opening. Then, a conductive layer is filled in the deep trench opening.

Abstract: A substrate is provided having an oxide layer, a first nitride-silicon, a STI, and a second nitride-silicon. A pattern poly-silicon layer on the second nitride-silicon layer is etched to form a deep trench opening. Etching the pattern poly-silicon layer also deepens the deep trench opening. Then, a conductive layer is filled in the deep trench opening.

Abstract: A trench capacitor structure includes a semiconductor substrate comprising thereon a STI structure. A capacitor deep trench is etched into the semiconductor substrate. Collar oxide layer is disposed on inner surface of the capacitor deep trench. A first doped polysilicon layer is disposed on the collar oxide layer and on the exposed bottom of the capacitor deep trench. A capacitor dielectric layer is formed on the first doped polysilicon layer. A second doped polysilicon layer is formed on the capacitor dielectric layer. A deep ion well is formed in the semiconductor substrate, wherein the deep ion well is electrically connected with the first doped polysilicon layer through the bottom of the capacitor deep trench. A passing gate insulation (PGI) layer is formed on the second doped polysilicon layer and on the STI structure.

Abstract: A substrate is provided having an oxide layer, a first nitride-silicon, a STI, and a second nitride-silicon. A pattern poly-silicon layer on the second nitride-silicon layer is etched to form a deep trench opening. Etching the pattern poly-silicon layer also deepens the deep trench opening. Then, a conductive layer is filled in the deep trench opening.

Abstract: A dynamic random access memory including a substrate, an isolation structure, two transistors, two trench capacitors and two passing gates is provided. The isolation structure, including a first isolation structure and a second isolation structure, is disposed in the substrate. The second isolation structure is disposed in the substrate above the first isolation structure and the bottom surface of the second isolation structure is lower than the top surface of the substrate. The periphery of the second isolation structure is beyond that of the first isolation structure. The transistors are disposed on the substrate respectively at two sides of the isolation structure. The trench capacitors are respectively disposed between the transistors and the isolation structures. A portion of the second isolation structure is disposed in the trench capacitor. The passing gates are completely disposed on the second isolation structure.

Abstract: A dynamic random access memory including a substrate, an isolation structure, two transistors, two trench capacitors and two passing gates is provided. The isolation structure, including a first isolation structure and a second isolation structure, is disposed in the substrate. The second isolation structure is disposed in the substrate above the first isolation structure and the bottom surface of the second isolation structure is lower than the top surface of the substrate. The periphery of the second isolation structure is beyond that of the first isolation structure. The transistors are disposed on the substrate respectively at two sides of the isolation structure. The trench capacitors are respectively disposed between the transistors and the isolation structures. A portion of the second isolation structure is disposed in the trench capacitor. The passing gates are completely disposed on the second isolation structure.

Abstract: A trench capacitor structure includes a semiconductor substrate comprising thereon a STI structure. A capacitor deep trench is etched into the semiconductor substrate. Collar oxide layer is disposed on inner surface of the capacitor deep trench. A first doped polysilicon layer is disposed on the collar oxide layer and on the exposed bottom of the capacitor deep trench. A capacitor dielectric layer is formed on the first doped polysilicon layer. A second doped polysilicon layer is formed on the capacitor dielectric layer. A deep ion well is formed in the semiconductor substrate, wherein the deep ion well is electrically connected with the first doped polysilicon layer through the bottom of the capacitor deep trench. A passing gate insulation (PGI) layer is formed on the second doped polysilicon layer and on the STI structure.

Abstract: A substrate is provided having an oxide layer, a first nitride-silicon, a STI, and a second nitride-silicon. A pattern poly-silicon layer on the second nitride-silicon layer is etched to form a deep trench opening. Etching the pattern poly-silicon layer also deepens the deep trench opening. Then, a conductive layer is filled in the deep trench opening.

Abstract: A fuse structure for a semiconductor device is provided. The fuse structure includes a fuse layer between the upper and bottom insulating layers. The fuse layer is connected to the other metal layers through via plugs. The fuse layer includes separate blocks and at least a connecting block and is coupled to at least a heat buffer block of a different layer. Because the heat buffer block is coupled to the blocks of the fuse layer, new fusing point and a new path for effectively dissipating the heat are provided and a longer and sinuous electric current path is obtained between the blocks through the heat buffer blocks. The heat buffer block and the blocks coupled to the heat buffer block can avoid large current flowing through the fuse structure and prevent overheating.

Abstract: A fuse structure for a semiconductor device is provided. The fuse structure includes a fuse layer between the upper and bottom insulating layers. The fuse layer is connected to the other metal layers through via plugs. The fuse layer includes separate blocks and at least a connecting block and is coupled to at least a heat buffer block of a different layer. Because the heat buffer block is coupled to the blocks of the fuse layer, new fusing point and a new path for effectively dissipating the heat are provided and a longer and sinuous electric current path is obtained between the blocks through the heat buffer blocks. The heat buffer block and the blocks coupled to the heat buffer block can avoid large current flowing through the fuse structure and prevent overheating.