Abstract: A semiconductor device and a method for forming the same are provided. The semiconductor device includes a substrate, a buffer layer on the substrate, a channel layer on the buffer layer, a barrier layer on the channel layer and a gate structure on the barrier layer. The gate structure includes a gate layer, a gate electrode layer, a first protection pattern layer and second protection spacers. The gate electrode layer covers the gate layer. The first protection pattern layer covers a first top surface of the gate electrode layer. The second protection spacers cover first side surfaces of the gate electrode layer, second side surfaces of the first protection pattern layer and a portion of the gate layer. First interfaces between the second protection spacers and the gate layer are coplanar with a second interface, which is between the gate electrode layer and the gate layer.

Abstract: A high electron mobility transistor structure includes a compound semiconductor channel layer disposed on a substrate, a compound semiconductor barrier layer disposed on the compound semiconductor channel layer, and a compound semiconductor cap layer disposed on the compound semiconductor barrier layer. The compound semiconductor cap layer includes a first segment and a second segment arranged along a first direction, and a gap between the first segment and the second segment. A gate electrode is disposed on the compound semiconductor cap layer. A source electrode and a drain electrode are disposed on the compound semiconductor barrier layer, arranged along a second direction and respectively located on two sides of the compound semiconductor cap layer.

Abstract: A semiconductor device includes a substrate having an active element region and a passive element region. A compound semiconductor channel layer, a compound semiconductor barrier layer and a first compound semiconductor cap layer are disposed in sequence on the substrate and located in the active element region. A gate electrode is disposed on the first compound semiconductor cap layer. A source electrode and a drain electrode are disposed on the compound semiconductor barrier layer and located on two opposite sides of the gate electrode, respectively, to construct a high electron mobility transistor. A second compound semiconductor cap layer is disposed on the substrate and located in the passive element region to construct a resistor.

Abstract: A high electron mobility transistor includes a substrate, a compound semiconductor stacked layer, a cap layer, a gate electrode, a source electrode, a drain electrode, and a buried electrode and/or a conductive structure. The substrate has an active area. The cap layer is disposed on the compound semiconductor stacked layer. The gate electrode is disposed on the cap layer and extends along a first direction. The source electrode and the drain electrode are disposed on the compound semiconductor stacked layer, respectively on two sides of the gate electrode, and arranged along a second direction, where the first direction is perpendicular to the second direction. The conductive structure and/or the buried electrode passes through the compound semiconductor stacked layer and surrounds or lies in the active area, where the conductive structure and/or the buried electrode has a constant electric potential or is grounded.

Abstract: A semiconductor structure is provided. The semiconductor structure includes a substrate, a channel layer, a barrier layer, a compound semiconductor layer, a gate electrode, and a stack of dielectric layers. The channel layer is disposed on the substrate. The barrier layer is disposed on the channel layer. The compound semiconductor layer is disposed on the barrier layer. The gate electrode is disposed on the compound semiconductor layer. The stack of dielectric layers is disposed on the gate electrode. The stack of dielectric layers includes layers having different etching rates.

Abstract: A semiconductor device is provided. The semiconductor device includes a substrate, a first III-V compound layer disposed on the substrate, a second III-V compound layer disposed on the first III-V compound layer, a p-type doped III-V compound layer disposed on the second III-V compound layer, a gate disposed over the p-type doped III-V compound layer, a source and a drain disposed on opposite sides of the gate, and a dielectric layer disposed between the p-type doped III-V compound layer and the gate. A method for forming the above semiconductor device is also provided.

Abstract: A semiconductor structure is provided. The semiconductor structure includes a substrate, a buffer layer, a barrier layer, a dielectric layer, a source structure, and a drain structure. The buffer layer is disposed on the substrate. The barrier layer is disposed on the buffer layer. The dielectric layer is disposed on the barrier layer. The passivation layer is disposed on the dielectric layer. The source structure and the drain structure are disposed on the passivation layer.

Abstract: A semiconductor structure includes a substrate, a gate structure on the substrate, and a source structure and a drain structure on opposite sides of the gate structure. The gate structure includes a gate electrode on the substrate and a gate metal layer on the gate electrode. The gate metal layer has at least one notch, which exposes the gate electrode below. The electric potential of the source structure is different from that of the gate structure.

Abstract: A semiconductor device includes an insulating layer, a semiconductor layer, and a compound semiconductor stacked layer disposed on a substrate in sequence, a first transistor, a second transistor, an isolation structure, and a conductive structure. The first transistor is disposed in a first device region and on the compound semiconductor stacked layer. The second transistor is disposed in a second device region and on the compound semiconductor stacked layer. The isolation structure is disposed between the first and second transistors. The conductive structure is disposed in the second device region, passes through the compound semiconductor stacked layer, and electrically connects the semiconductor layer to a second source of the second transistor. There is no electrical connection between the semiconductor layer in the first device region and a first source of the first transistor.

Abstract: A semiconductor structure includes a substrate, a channel layer, a barrier layer, a source structure, a drain structure, a doped compound semiconductor layer, a dielectric layer, and a gate structure. The channel layer is disposed on the substrate. The barrier layer is disposed on the channel layer. The source structure and the drain structure are disposed on opposite sides of the barrier layer. The doped compound semiconductor layer is disposed on the barrier layer. The doped compound semiconductor layer has a first side adjacent to the source structure and a second side adjacent to the drain structure. The doped compound semiconductor layer has at least one opening exposing at least a portion of the barrier layer. The dielectric layer is disposed on the doped compound semiconductor layer and the barrier layer. The gate structure is disposed on the doped compound semiconductor layer.

Abstract: A semiconductor device is provided, including a substrate, a seed layer on the substrate, an epitaxial layer on the seed layer, an electrode structure on the epitaxial layer and an electric field modulation structure. The electrode structure includes a gate structure, a source structure and a drain structure, wherein the source structure and the drain structure are positioned on opposite sides of the gate structure. The electric field modulation structure includes an electric connection structure and a conductive layer electrically connected to the electric connection structure. The conductive layer is positioned between the gate structure and the drain structure. The electric connection structure is electrically connected to the source structure and the drain structure.

Abstract: A high electron mobility transistor includes a substrate, a compound semiconductor stacked layer, a cap layer, a gate electrode, a source electrode, a drain electrode, and a buried electrode and/or a conductive structure. The substrate has an active area. The cap layer is disposed on the compound semiconductor stacked layer. The gate electrode is disposed on the cap layer and extends along a first direction. The source electrode and the drain electrode are disposed on the compound semiconductor stacked layer, respectively on two sides of the gate electrode, and arranged along a second direction, where the first direction is perpendicular to the second direction. The conductive structure and/or the buried electrode passes through the compound semiconductor stacked layer and surrounds or lies in the active area, where the conductive structure and/or the buried electrode has a constant electric potential or is grounded.

Abstract: A semiconductor device including a substrate, a seed layer, a buffer layer, a channel layer, a barrier layer, a gate structure, a first source/drain structure, a second source/drain structure, and a contact is provided. The seed layer is disposed on the substrate. The buffer layer is disposed on the seed layer. The channel layer is disposed on the buffer layer. The barrier layer is disposed on the channel layer. The gate structure is disposed on the barrier layer. The first and second source/drain structures are disposed on opposite sides of the gate structure. The contact contacts the first source/drain structure. The distance between the gate structure and the contact is between 0.5 micrometers and 30 micrometers.

Abstract: A semiconductor device including a substrate, a seed layer, a buffer layer, a channel layer, a barrier layer, a gate structure, a first source/drain structure, a second source/drain structure, and a contact is provided. The seed layer is disposed on the substrate. The buffer layer is disposed on the seed layer. The channel layer is disposed on the buffer layer. The barrier layer is disposed on the channel layer. The gate structure is disposed on the barrier layer. The first and second source/drain structures are disposed on opposite sides of the gate structure. The contact contacts the first source/drain structure. The distance between the gate structure and the contact is between 0.5 micrometers and 30 micrometers.

Abstract: A semiconductor structure is provided. The semiconductor structure includes a substrate, a channel layer, a barrier layer, a compound semiconductor layer, a gate electrode, and a stack of dielectric layers. The channel layer is disposed on the substrate. The barrier layer is disposed on the channel layer. The compound semiconductor layer is disposed on the barrier layer. The gate electrode is disposed on the compound semiconductor layer. The stack of dielectric layers is disposed on the gate electrode. The stack of dielectric layers includes layers having different etching rates.

Abstract: A semiconductor device is provided, including a substrate, a seed layer on the substrate, an epitaxial layer on the seed layer, an electrode structure on the epitaxial layer and an electric field modulation structure. The electrode structure includes a gate structure, a source structure and a drain structure, wherein the source structure and the drain structure are positioned on opposite sides of the gate structure. The electric field modulation structure includes an electric connection structure and a conductive layer electrically connected to the electric connection structure. The conductive layer is positioned between the gate structure and the drain structure. The electric connection structure is electrically connected to the source structure and the drain structure.

Abstract: A semiconductor structure includes a substrate, a channel layer, a barrier layer, a source structure, a drain structure, a doped compound semiconductor layer, a dielectric layer, and a gate structure. The channel layer is disposed on the substrate. The barrier layer is disposed on the channel layer. The source structure and the drain structure are disposed on opposite sides of the barrier layer. The doped compound semiconductor layer is disposed on the barrier layer. The doped compound semiconductor layer has a first side adjacent to the source structure and a second side adjacent to the drain structure. The doped compound semiconductor layer has at least one opening exposing at least a portion of the barrier layer. The dielectric layer is disposed on the doped compound semiconductor layer and the barrier layer. The gate structure is disposed on the doped compound semiconductor layer.

Abstract: A semiconductor structure includes a substrate having a first region and a second region, an epitaxial layer above the substrate, a first device on the first region, a second device on the second region and an isolation structure on the substrate. The first device includes a first gate electrode, a first source electrode and a first drain electrode disposed at two opposite sides of the first gate electrode. A dielectric layer disposed on the epitaxial layer covers the first gate electrode. The second device includes a second gate electrode disposed on the dielectric layer, second source and drain electrodes disposed at two opposite sides of the second gate electrode. The second source electrode is electrically connected to the first drain electrode. Also, the portions of the epitaxial layer respectively disposed in the first and second regions are isolated from each other by the isolation structure.

Abstract: A semiconductor structure includes a substrate having a first region and a second region, an epitaxial layer above the substrate, a first device on the first region, a second device on the second region and an isolation structure on the substrate. The first device includes a first gate electrode, a first source electrode and a first drain electrode disposed at two opposite sides of the first gate electrode. A dielectric layer disposed on the epitaxial layer covers the first gate electrode. The second device includes a second gate electrode disposed on the dielectric layer, second source and drain electrodes disposed at two opposite sides of the second gate electrode. The second source electrode is electrically connected to the first drain electrode. Also, the portions of the epitaxial layer respectively disposed in the first and second regions are isolated from each other by the isolation structure.

Abstract: A semiconductor structure includes a substrate, a gate structure on the substrate, and a source structure and a drain structure on opposite sides of the gate structure. The gate structure includes a gate electrode on the substrate and a gate metal layer on the gate electrode. The gate metal layer has at least one notch, which exposes the gate electrode below. The electric potential of the source structure is different from that of the gate structure.