A normally-off HEMT transistor includes a heterostructure including a channel layer and a barrier layer on the channel layer; a 2DEG layer in the heterostructure; an insulation layer in contact with a first region of the barrier layer; and a gate electrode through the whole thickness of the insulation layer, terminating in contact with a second region of the barrier layer. The barrier layer and the insulation layer have a mismatch of the lattice constant (“lattice mismatch”), which generates a mechanical stress solely in the first region of the barrier layer, giving rise to a first concentration of electrons in a first portion of the two-dimensional conduction channel which is under the first region of the barrier layer which is greater than a second concentration of electrons in a second portion of the two-dimensional conduction channel which is under the second region of the barrier layer.

A method for making a multilayered device on an engineered substrate having a substrate coefficient of thermal expansion includes growing a buffer layer on the engineered substrate, and growing a first epitaxial layer on the buffer layer. The first epitaxial layer is characterized by an epitaxial coefficient of thermal expansion substantially equal to the substrate coefficient of thermal expansion.

A semiconductor device comprising stacked complimentary transistors are described. In some embodiments, the semiconductor device comprises a first device comprising an enhancement mode III-N heterostructure field effect transistor (HFET), and a second device over the first device. In an example, the second device comprises a depletion mode thin film transistor. In an example, a connector is to couple a first terminal of the first device to a first terminal of the second device.

A high electron mobility transistor includes a stack of layers including a passivation layer and a heterojunction including a first semiconductor layer, a second semiconductor layer and a two-dimensional electron gas at the interface thereof, one surface of the passivation layer being in contact with the first semiconductor layer; a source metal contact and/or a drain metal contact and a gate electrode; an n+ doped zone situated inside the heterojunction; the source metal contact and/or the drain metal contact being positioned at the level of a recess formed in the stack of layers, the source metal contact and/or said drain metal contact having a thickness defined by an upper face and a lower face substantially parallel to the plane of the layers, the upper face being planar, the lower face being in contact with the n+ doped zone and below the interface between the first and second semiconductor layers.

An N-polar III-N high-electron mobility transistor device can include a III-N channel layer over an N-face of a III-N backbarrier, wherein a compositional difference between the channel layer and the backbarrier causes a 2DEG channel to be induced in the III-N channel layer adjacent to the interface between the III-N channel layer and the backbarrier. The device can further include a p-type III-N layer over the III-N channel layer and a thick III-N cap layer over the p-type III-N layer. The III-N cap layer can cause an increase in the charge density of the 2DEG channel directly below the cap layer, and the p-type III-N layer can serve to prevent a parasitic 2DEG from forming in the III-N cap layer.

A high electron mobility transistor includes: a first semiconductor layer over a substrate, and a second semiconductor layer over the first semiconductor layer, the second semiconductor layer having a band gap discontinuity with the first semiconductor layer, and at the first semiconductor layer and/or the second conductive layer includes indium. A top layer is over the second semiconductor layer, and a metal layer is over, and extends into, the top layer, the top layer separating the metal layer from the second semiconductor layer. A gate electrode is over the top layer, a third semiconductor layer being between the gate electrode and the top layer, where a sidewall of the third semiconductor layer and a sidewall of the metal layer are separated. A source and drain are on opposite sides of the gate electrode, the top layer extending continuously from below the source, below the gate electrode, and below the drain.

A bonded semiconductor device including an epitaxial layer, and a support substrate made of a material different from that of the epitaxial layer and bonded to the epitaxial layer. Any one of the epitaxial layer and the support substrate has a bonding surface with a radial pattern including recesses or protrusions radially spreading from a certain point on the bonding surface as a center.

A compound semiconductor substrate and a method for manufacturing the same are provided to suppress surface roughness of a barrier layer while suppressing gate leak.

A method for manufacturing of a compound semiconductor substrate comprises a step forming an electronic traveling layer consisting of a first nitride semiconductor, a step forming a barrier layer consisting of a second nitride semiconductor with a wider band gap than a band gap of the first nitride semiconductor on the electronic traveling layer, and a step forming a cap layer with an organometallic vapor phase epitaxy on the barrier layer and in contact with the barrier layer. The cap layer has a C concentration of 5*10.sup.17 atoms/cm.sup.3 or more and 1*10.sup.20 atoms/cm.sup.3 or less, and consists of a nitride semiconductor. During the step forming the cap layer, source gas of the nitride semiconductor forming the cap layer and hydrocarbon gas are introduced to a top surface of the barrier layer.

A device includes a diode that includes a first group III-nitride (III-N) material and a transistor adjacent to the diode, where the transistor includes the first III-N material. The diode includes a second III-N material, a third III-N material between the first III-N material and the second III-N material, a first terminal including a metal in contact with the third III-N material, a second terminal coupled to the first terminal through the first group III-N material. The device further includes a transistor structure, adjacent to the diode structure. The transistor structure includes the first, second, and third III-N materials, a source and drain, a gate electrode and a gate dielectric between the gate electrode and each of the first, second and third III-N materials.

Embodiments are directed to high electron mobility transistor (HEMT) devices and methods. One such HEMT device includes a substrate having a first surface, and first and second heterostructures on the substrate and facing each other. Each of the first and second heterostructures includes a first semiconductor layer on the first surface of the substrate, a second semiconductor layer on the first surface of the substrate, and a two-dimensional electrode gas (2DEG) layer between the first and second semiconductor layers. A doped semiconductor layer is disposed between the first and second heterostructures, and a source contact is disposed on the first heterostructure and the second heterostructure.