Abstract: Provided are a high electron mobility transistor (HEMT) and a method of manufacturing the HEMT. The HEMT includes: a channel layer comprising a first semiconductor material; a channel supply layer comprising a second semiconductor material and generating two-dimensional electron gas (2DEG) in the channel layer; a source electrode and a drain electrode separated from each other in the channel supply layer; at least one depletion forming unit that is formed on the channel supply layer and forms a depletion region in the 2DEG; at least one gate electrode that is formed on the at least one depletion forming unit; at least one bridge that connects the at least one depletion forming unit and the source electrode; and a contact portion that extends from the at least one bridge under the source electrode.

Abstract: According to example embodiments, a high electron mobility transistor (HEMT) includes a channel layer having a 2-dimensional electron gas (2DEG), a channel supply layer on the channel layer, a source electrode and a drain electrode spaced apart from each other on one of the channel layer and the channel supply layer, at least one channel depletion layer on the channel supply layer; a gate electrode on at least a part of the channel depletion layer, and at least one bridge connecting the channel depletion layer and the source electrode. The channel depletion layer is configured to form a depletion region in the 2DEG. The HEMT has a ratio of a first impedance to a second impedance that is a uniform value. The first impedance is between the gate electrode and the channel depletion layer. The second impedance is between the source electrode and the channel depletion layer.

Abstract: According to example embodiments, a high electron mobility transistor (HEMT) includes a channel layer; a channel supply layer on the channel layer; a source electrode and a drain electrode spaced apart from each other on one of the channel layer and the channel supply layer; a gate electrode on a part of the channel supply layer between the source electrode and the drain electrode; a first depletion-forming layer between the gate electrode and the channel supply layer; and a at least one second depletion-forming layer on the channel supply layer between the gate electrode and the drain electrode. The at least one second depletion-forming layer is electrically connected to the source electrode.

Abstract: High electron mobility transistors (HEMTs) including a cavity below a drain and methods of manufacturing HEMTS including removing a portion of a substrate below a drain.

Abstract: A high electron mobility transistor (HEMT) according to example embodiments includes a channel layer, a channel supply layer on the channel layer, a source electrode and a drain electrode on at least one of the channel layer and the channel supply layer, a gate electrode between the source electrode and the drain electrode, and a Schottky electrode forming a Schottky contact with the channel supply layer. An upper surface of the channel supply layer may define a Schottky electrode accommodation unit. At least part of the Schottky electrode may be in the Schottky electrode accommodation unit. The Schottky electrode is electrically connected to the source electrode.

Abstract: According to example embodiments, a power device chip includes a plurality of unit power devices classified into a plurality of sectors, a first pad and a second pad. At least one of the first and second pads is divided into a number of pad parts equal to a number of the plurality of sectors. The first pad is connected to first electrodes of the plurality of unit power devices, and the second pad is connected to second electrodes of the plurality of unit power devices. The unit power devices may be diodes. The power device chip may further include third electrodes in the plurality of unit power devices, and a third pad may be connected to the third electrodes. In this case, the unit power devices may be high electron mobility transistors (HEMTs). Pad parts connected to defective sectors may be excluded from bonding.

Abstract: According to example embodiments, a high electron mobility transistor (HEMT) includes a channel supply layer and a channel layer. The channel layer may include an effective channel region and a high resistivity region. The effective channel region may be between the high resistivity region and the channel supply layer. The high resistivity region may be a region into which impurities are ion-implanted. According to example embodiments, a method of forming a HEMT includes forming a device unit, including a channel layer and a channel supply layer, on a first substrate; adhering a second substrate to the device unit; removing the first substrate; and forming a high resistivity region by ion-implanting impurities into at least a portion of the channel layer.

Abstract: According to example embodiments, a HEMT includes a channel supply layer on a channel layer, a p-type semiconductor structure on the channel supply layer, a gate electrode on the p-type semiconductor structure, and source and drain electrodes spaced apart from two sides of the gate electrode respectively. The channel supply layer may have a higher energy bandgap than the channel layer. The p-type semiconductor structure may have an energy bandgap that is different than the channel supply layer. The p-type semiconductor structure may include a hole injection layer (HIL) on the channel supply layer and be configured to inject holes into at least one of the channel layer and the channel supply in an on state. The p-type semiconductor structure may include a depletion forming layer on part of the HIL. The depletion forming layer may have a dopant concentration that is different than the dopant concentration of the HIL.

Abstract: High electron mobility transistors (HEMTs) including a substrate and a HEMT stack on the substrate, the HEMT stack including a compound semiconductor layer that includes a 2-dimensional electron gas (2DEG), an upper compound semiconductor layer that has a polarization index higher than a polarization index of the compound semiconductor layer, and a source electrode, a drain electrode, and a gate that are disposed on the upper compound semiconductor layer. The substrate may be a nitride substrate that has a dielectric constant and a thermal conductivity higher than a dielectric constant and a thermal conductivity of a silicon substrate. The substrate may include an insulating layer that has a dielectric constant and a thermal conductivity higher than a dielectric constant and a thermal conductivity of the silicon substrate, a metal layer that is deposited on the insulating layer, and a plate that is attached to the metal layer.

Abstract: The methods may include forming a first material layer on a substrate, increasing electric resistance of the first material layer, and forming a source pattern and a drain pattern, which are spaced apart from each other, on the first material layer, a band gap of the source and drain patterns greater than a band gap of a first material layer.

Abstract: According to example embodiments, a high electron mobility transistor includes: a channel layer including a 2-dimensional electron gas (2DEG); a contact layer on the channel layer; a channel supply layer on the contact layer; a gate electrode on a portion of the channel layer; and source and drain electrodes on at least one of the channel layer, the contact layer, and the channel supply layer. The contact layer is configured to form an ohmic contact on the channel layer. The contact layer is n-type doped and contains a Group III-V compound semiconductor. The source electrode and the drain electrode are spaced apart from opposite sides of the gate electrode.

Abstract: High electron mobility transistors (HEMTs) and methods of manufacturing the same. A HEMT may include a source electrode, a gate electrode, a drain electrode, a channel formation layer including at least a 2-dimensional electron gas (2DEG) channel, a channel supplying layer for forming the 2DEG channel in the channel formation layer, a portion of the channel supplying layer including a first oxygen treated region. The channel supplying layer may include a second oxygen treated region that extends from the first oxygen treated region towards the drain electrode, and the depth and concentration of oxygen of the second oxygen treated region may be less than those of the first oxygen treated region.

Abstract: Provided are a high electron mobility transistor and/or a method of manufacturing the same. The high electron mobility transistor includes a channel layer, a channel supply layer formed on the channel layer to generate a two-dimensional electron gas (2DEG), a depletion forming layer formed on the channel supply layer, a gate electrode formed on the depletion forming layer, and a barrier layer formed between the depletion forming layer and the gate electrode. Holes may be prevented from being injected into the depletion forming layer from the gate electrode, thereby reducing a gate forward current.

Abstract: According to example embodiments, a high electron mobility transistor (HEMT) includes a channel layer having a 2-dimensional electron gas (2DEG), a channel supply layer on the channel layer, a source electrode and a drain electrode spaced apart from each other on one of the channel layer and the channel supply layer, at least one channel depletion layer on the channel supply layer; a gate electrode on at least a part of the channel depletion layer, and at least one bridge connecting the channel depletion layer and the source electrode. The channel depletion layer is configured to form a depletion region in the 2DEG. The HEMT has a ratio of a first impedance to a second impedance that is a uniform value. The first impedance is between the gate electrode and the channel depletion layer. The second impedance is between the source electrode and the channel depletion layer.

Abstract: An electrode structure, a GaN-based semiconductor device including the electrode structure, and methods of manufacturing the same, may include a GaN-based semiconductor layer and an electrode structure on the GaN-based semiconductor layer. The electrode structure may include an electrode element including a conductive material and a diffusion layer between the electrode element and the GaN-based semiconductor layer. The diffusion layer may include a material which is an n-type dopant with respect to the GaN-based semiconductor layer, and the diffusion layer may contact the GaN-based semiconductor layer. A region of the GaN-based semiconductor layer contacting the diffusion layer may be doped with the n-type dopant. The material of the diffusion layer may comprise a Group 4 element.

Abstract: The present invention relates to a method for transmitting a plurality of asynchronous signals, which includes: transmitting to a plurality of audio synchronizers a plurality of asynchronous audio signals which is detected by different audio input devices and is not synchronized with each other; synchronizing, by the plurality of audio synchronizers, the plurality of asynchronous audio signals, respectively; and multiplexing, by a multiple-channel time-division multiplexer, the plurality of synchronized audio signals to a multiple-channel time-division audio signal.

Abstract: A High electron mobility transistor (HEMT) includes a source electrode, a gate electrode, a drain electrode, a channel forming layer in which a two-dimensional electron gas (2DEG) channel is induced, and a channel supplying layer for inducing the 2DEG channel in the channel forming layer. The source electrode and the drain electrode are located on the channel supplying layer. A channel increase layer is between the channel supplying layer and the source and drain electrodes. A thickness of the channel supplying layer is less than about 15 nm.

Abstract: According to example embodiments, a substrate structure may include a GaN-based third material layer, a GaN-based second material layer, a GaN-based first material layer, and a buffer layer on a non-GaN-based substrate. The GaN-based first material layer may be doped with a first conductive type impurity. The GaN-based second material layer may be doped with a second conductive type impurity at a density that is less than a density of the first conductive type impurity in the first GaN-based material layer. The GaN-based third material layer may be doped with a first conductive type impurity at a density that is less than the density of the first conductive type impurity of the GaN-based first material layer. After a second substrate is attached onto the substrate structure, the non-GaN-based substrate may be removed and a GaN-based vertical type semiconductor device may be fabricated on the second substrate.

Abstract: A method for forming a selective ohmic contact for a Group III-nitride heterojunction structured device may include forming a conductive layer and a capping layer on an epitaxial substrate including at least one Group III-nitride heterojunction layer and having a defined ohmic contact region, the capping layer being formed on the conductive layer or between the conductive layer and the Group III-nitride heterojunction layer in one of the ohmic contact region and non-ohmic contact region, and applying at least one of a laser annealing process and an induction annealing process on the substrate at a temperature of less than or equal to about 750° C. to complete the selective ohmic contact in the ohmic contact region.

Abstract: Provided are a high electron mobility transistor (HEMT) and a method of manufacturing the HEMT. The HEMT includes: a channel layer comprising a first semiconductor material; a channel supply layer comprising a second semiconductor material and generating two-dimensional electron gas (2DEG) in the channel layer; a source electrode and a drain electrode separated from each other in the channel supply layer; at least one depletion forming unit that is formed on the channel supply layer and forms a depletion region in the 2DEG; at least one gate electrode that is formed on the at least one depletion forming unit; at least one bridge that connects the at least one depletion forming unit and the source electrode; and a contact portion that extends from the at least one bridge under the source electrode.