A semiconductor device includes a first nitride semiconductor layer having a first region, a second nitride semiconductor layer that is on the first nitride semiconductor layer and contains carbon and silicon, a third nitride semiconductor layer that is on the second nitride semiconductor layer and has a second region, a fourth nitride semiconductor layer on the third nitride semiconductor layer, the fourth nitride semiconductor layer having a band gap that is wider than a band gap of the third nitride semiconductor layer, a source electrode that is on the fourth nitride semiconductor layer and is electrically connected to the first region, a drain electrode that is on the fourth nitride semiconductor layer and is electrically connected to the second region, and a gate electrode that is on the fourth nitride semiconductor layer and is between the source electrode and the drain electrode.

A method for fabricating Complementary Metal Oxide Semiconductor (CMOS) compatible contact layers in semiconductor devices is disclosed. In one embodiment, a nickel (Ni) layer is deposited on a p-type gallium nitride (GaN) layer of a GaN based structure. Further, the GaN based structure is thermally treated at a temperature range of 350 C. to 500 C. Furthermore, the Ni layer is removed using an etchant. Additionally, a CMOS compatible contact layer is deposited on the p-type GaN layer, upon removal of the Ni layer.

A semiconductor arrangement is produced by providing a semiconductor carrier of a second conduction type and epitaxially growing a first semiconductor zone of a first conduction type on the carrier. The first semiconductor zone includes a semiconductor base material doped with first and second dopants which are made of different substances which are both different from the semiconductor base material. The first dopant is electrically active and causes a doping of the first conduction type in the semiconductor base material, and causes a decrease or an increase of a lattice constant of the first semiconductor zone. The second dopant causes one or both of hardening of the first semiconductor zone and an increase of the lattice constant of the first semiconductor zone if the first dopant causes a decrease, or a decrease of the lattice constant of the first semiconductor zone if the first dopant causes an increase.

A transistor device includes a channel, a first source/drain region positioned on a first side of the channel, a second source/drain region positioned on a second side of the channel opposite the first side of the channel, and a tunnel barrier disposed between the channel and the first source/drain region, the tunnel barrier adapted to suppress band-to-band tunneling while the transistor device is in an off state.

A IIIA-VA group semi-conductor single crystal substrate (2) has one of or both of the following two properties: an oxygen content of 1.610.sup.16-5.610.sup.17 atoms/cm.sup.3 in a range from the surface to a depth of 10 m of the wafer, and an electron mobility of 4,800 cm.sup.2/V.Math.s-5,850 cm.sup.2/V.Math.s. Further, a method for preparing the semi-conductor single crystal substrate (2) comprises: placing a single crystal substrate (2) to be processed in a container (4); sealing said container (4), and keeping said single crystal substrate (2) to be processed at a temperature in the range of from the crystalline melting point 240 C. to the crystalline melting point 30 C. for 5 hours to 20 hours; preferably, keeping a gallium arsenide single crystal at a temperature of 1,000 C. to 1,200 C. for 5 hours to 20 hours.

A high electron mobility transistor (HEMT) device with a highly resistive layer co-doped with carbon (C) and a donor-type impurity and a method for making the HEMT device is disclosed. In one embodiment, the HEMT device includes a substrate, the highly resistive layer co-doped with C and the donor-type impurity formed above the substrate, a channel layer formed above the highly resistive layer, and a barrier layer formed above the channel layer. In one embodiment, the highly resistive layer comprises gallium nitride (GaN). In one embodiment, the donor-type impurity is silicon (Si). In another embodiment, the donor-type impurity is oxygen (O).

A semiconductor device comprises a first layer of a substrate arranged on a second layer of the substrate the second layer of the substrate including a doped III-V semiconductor material barrier layer, a gate stack arranged on a channel region of the first layer of a substrate, a spacer arranged adjacent to the gate stack on the first layer of the substrate, an undoped epitaxially grown III-V semiconductor material region arranged on the second layer of the substrate, and an epitaxially grown source/drain region arranged on the undoped epitaxially grown III-V semiconductor material region, and a portion of the first layer of the substrate.

The present invention discloses an electronic device using a group III nitride substrate fabricated via the ammonothermal method. By utilizing the high-electron concentration of ammonothermally grown substrates having the dislocation density less than 10.sup.5 cm.sup.2, combined with a high-purity active layer of Ga.sub.1-x-yAl.sub.xIn.sub.yN (0x1, 0y1) grown by a vapor phase method, the device can attain high level of breakdown voltage as well as low on-resistance. To realize a good matching between the ammonothermally grown substrate and the high-purity active layer, a transition layer is optionally introduced. The active layer is thicker than a depletion region created by a device structure in the active layer.

A semiconductor device comprises a semiconductor substrate; a channel layer of at least one III-V semiconductor compound above the semiconductor substrate; a gate electrode above a first portion of the channel layer; a source region and a drain region above a second portion of the channel layer; and a dopant layer comprising at least one dopant contacting the second portion of the channel layer.

A III-nitride structure can include a silicon substrate, a nucleation layer over the silicon substrate, and a carbon-doped buffer layer over the nucleation layer. The carbon-doped buffer layer can include a III-nitride material and a concentration of carbon that is greater than 110.sup.20 cm.sup.3. The III-nitride structure can include a III-nitride channel layer over the carbon-doped buffer layer and a III-nitride barrier layer over the III-nitride channel layer. The carbon doping to a carbon concentration greater than 110.sup.20 cm.sup.3 can increase the compressive stress in the III-nitride structure.