A semiconductor structure includes a buffer layer, a channel layer, a barrier layer, a doped compound semiconductor layer, and a composition gradient layer. The buffer layer is disposed on a substrate, the channel layer is disposed on the buffer layer, the barrier layer is disposed on the channel layer, the doped compound semiconductor layer is disposed on the barrier layer, and the composition gradient layer is disposed between the barrier layer and the doped compound semiconductor layer. The barrier layer and the composition gradient layer include a same group III element and a same group V element, and the atomic percentage of the same group III element in the composition gradient layer is gradually increased in the direction from the barrier layer to the doped compound semiconductor layer. A high electron mobility transistor and a fabrication method thereof are also provided.

A semiconductor structure includes: a channel layer; an active layer over the channel layer, wherein the active layer is configured to form a two-dimensional electron gas (2DEG) to be formed in the channel layer along an interface between the channel layer and the active layer; a gate electrode over a top surface of the active layer; and a source/drain electrode over the top surface of the active layer; wherein the active layer includes a first layer and a second layer sequentially disposed therein from the top surface to a bottom surface of the active layer, and the first layer possesses a higher aluminum (Al) atom concentration compared to the second layer. An HEMT structure and an associated method are also disclosed.

A semiconductor structure includes: a channel layer; an active layer over the channel layer, wherein the active layer is configured to form a two-dimensional electron gas (2DEG) to be formed in the channel layer along an interface between the channel layer and the active layer; a gate electrode over a top surface of the active layer; and a source/drain electrode over the top surface of the active layer; wherein the active layer includes a first layer and a second layer sequentially disposed therein from the top surface to a bottom surface of the active layer, and the first layer possesses a higher aluminum (Al) atom concentration compared to the second layer. An HEMT structure and an associated method are also disclosed.

A high electron mobility transistor (HEMT) includes a substrate; and a first semiconductor layer over the substrate. The HEMT further includes a second semiconductor layer over the first semiconductor layer, wherein the second semiconductor layer has a band gap discontinuity with the first semiconductor layer, and at least one of the first semiconductor layer or the second semiconductor layer comprises indium. The HEMT further includes a top layer over the second semiconductor layer. The HEMT further includes a gate electrode over the top layer. The HEMT further includes a source and a drain on opposite sides of the gate electrode, wherein the top layer extends continuously from below the source, below the gate electrode, and to below the drain.

The invention relates to a semiconductor component comprising at least one field effect transistor, said transistor comprising at least a back barrier layer, a buried layer arranged on the back barrier layer, a channel layer arranged on the buried layer, a barrier layer arranged on the channel layer, and a gate layer arranged on the barrier layer, wherein the barrier layer comprises Al.sub.zGa.sub.1-zN and wherein the buried layer comprises Al.sub.xGa.sub.1-xN and at least one dopant causing a p-type conductivity, and wherein the gate layer comprises any of GaN and/or Al.sub.uIn.sub.vGa.sub.1-v-uN. A field effect transistor according to the disclosure may be configured to show a gate threshold voltage which is higher than approximately 0.5 V or higher than approximately 1.0 V.

An insulated gate bipolar transistor includes a P-type group III-V nitride compound layer. An N-type group III-V nitride compound layer contacts a side of the P-type group III-V nitride compound layer. An HEMT is disposed on the N-type group III-V nitride compound layer. The HEMT includes a first group III-V nitride compound layer disposed on the N-type group III-V nitride compound layer. A second group III-V nitride compound layer is disposed on the first group III-V nitride compound layer. A source is embedded within the second group III-V nitride compound layer and the first group III-V nitride compound layer, wherein the source includes an N-type group III-V nitride compound body and a metal contact. A drain contacts another side of the P-type group III-V nitride compound layer. A gate is disposed on the second group III-V nitride compound layer.

A directed epitaxial heterojunction bipolar transistor (HBT) structure is directly or indirectly formed on a GaAs substrate that is formed by a (100) face towards a (111)B face with an angle of inclination between 0.6° and 25°, and includes a sub-collector layer, a collector, a base layer, an emitter layer, an emitter cap layer and an ohmic contact layer, which are sequentially formed on the substrate. A tunnel collector layer formed by InGaP or InGaAsP is provided between the collector layer and the base layer. Since an epitaxial process is performed on the substrate from a (100) face towards a (111)B face with an angle of inclination between 0.6° and 25°, indium and gallium contained in InGaP or InGaAsP are affected by the ordering effect such that InGaP or InGaAsP used in the emitter layer and/or the tunnel collector layer has a higher electron affinity or a smaller bandgap.

A directed epitaxial heterojunction bipolar transistor (HBT) structure is directly or indirectly formed on a GaAs substrate that is formed by a (100) face towards a (111)B face with an angle of inclination between 0.6° and 25°, and includes a sub-collector layer, a collector, a base layer, an emitter layer, an emitter cap layer and an ohmic contact layer, which are sequentially formed on the substrate. A tunnel collector layer formed by InGaP or InGaAsP is provided between the collector layer and the base layer. Since an epitaxial process is performed on the substrate from a (100) face towards a (111)B face with an angle of inclination between 0.6° and 25°, indium and gallium contained in InGaP or InGaAsP are affected by the ordering effect such that InGaP or InGaAsP used in the emitter layer and/or the tunnel collector layer has a higher electron affinity or a smaller bandgap.

A device comprising a III-N layer stack featuring a two-dimensional electron gas is disclosed, comprising: —a III-N layer; —a AI-III-N layer on top of the III-N layer; —a passivation layer on top of said AI-III-N layer, the passivation layer comprising Silicon Nitride (SiN); wherein said passivation layer comprises a fully crystalline sub layer at the AI-III-N interface and at least part of the fully crystalline sub layer comprises Al and/or B; and associated methods for manufacturing the device.

A device comprising a III-N layer stack featuring a two-dimensional electron gas is disclosed, comprising: —a III-N layer; —a AI-III-N layer on top of the III-N layer; —a passivation layer on top of said AI-III-N layer, the passivation layer comprising Silicon Nitride (SiN); wherein said passivation layer comprises a fully crystalline sub layer at the AI-III-N interface and at least part of the fully crystalline sub layer comprises Al and/or B; and associated methods for manufacturing the device.