Abstract: Provided is a laser welding apparatus for spacer grid of nuclear fuel assembly comprising a base frame in which a chamber installment hole is formed horizontally to the center in a way that the hole penetrates the chamber and a guide rail is installed along the chamber installment hole; a welding chamber unit assembled with the base frame in guidance by the guide rail and equipped with an operable door in front and a glass window at the top to be airtight; a laser welding unit mounted on the base frame for radiating laser through the glass window to weld spacer grid in the welding chamber; and a locking member for fixing the welding chamber on the base frame.

Abstract: An electronic device may include a first transistor having a normally-on characteristic; a second transistor connected to the first transistor and having a normally-off characteristic; a constant voltage application unit configured to apply a constant voltage to a gate of the first transistor; and a switching unit configured to apply a switching signal to the second transistor. The first transistor may be a high electron mobility transistor (HEMT). The second transistor may be a field-effect transistor (FET). The constant voltage application unit may include a diode connected to the gate of the first transistor; and a constant current source connected to the diode.

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: An apparatus for generating a virtual engine sound is provided. The apparatus includes a rotating bracket member that is disposed within a wheel of a vehicle and includes movement space therein, and elastic bodies, each of which has a first end fixed to a substantial rotation center position of the rotating bracket member. In addition, the apparatus includes weight bodies which are fixed to a second end of the elastic body, and are configured to move within the movement space based on a rotation speed of the wheel of the vehicle, and selectively contact the rotating bracket member.

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: This invention relates to a trench MOSFET, which can lower parasitic capacitance, thereby increasing a switching speed, and to a method of manufacturing the trench MOSFET. The trench MOSFET includes a substrate having an epi layer and a body layer sequentially formed thereon, a trench formed vertically in the central portion of the epi layer and the body layer, a first gate oxide film formed on the inner wall of the trench, a diffusion oxide film formed in the epi layer between the lower surface of the trench and the upper surface of the substrate to have a thickness greater than a thickness of the first gate oxide film and a width greater than a width of the trench, a gate formed in the trench having the first gate oxide film, a second gate oxide film formed on the gate, and a source region formed at both sides of the upper portion may be of the gate, thus reducing the generation of parasitic capacitance between the epi layer corresponding to a drain region and the gate, thereby improving a switching speed.

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: A power switching device includes a channel forming layer on a substrate which includes a 2-dimensional electron gas (2DEG), and a channel supply layer which corresponds to the 2DEG at the channel forming layer. A cathode is coupled to a first end of the channel supply layer and an anode is coupled to a second end of the channel supply layer. The channel forming layer further includes a plurality of depletion areas arranged in a pattern, and portions of the channel forming layer between the plurality of depletion areas are non-depletion areas.

Abstract: A semiconductor device and a fabricating method thereof are provided, in which the semiconductor device includes a semiconductor substrate with a trench formed therein, a bottom electrode placed at a lower inner portion of the trench, the bottom electrode having an uneven upper surface, an insulating layer formed on an upper portion of the bottom electrode and on a sidewall of the trench, and a top electrode placed at an upper portion of the bottom electrode inside the trench, the top electrode having a top electrode which is uneven, in which the top electrode is so configured that the top electrode is inclined toward a center portion.

Abstract: A semiconductor device includes a first compound semiconductor layer on a substrate, first through third electrodes spaced apart from each other on the first compound semiconductor layer, a second compound semiconductor layer on the first compound semiconductor layer between the first through third electrodes, a third compound semiconductor layer on the second compound semiconductor layer between the first and second electrodes, a first gate electrode on the third compound semiconductor layer, a fourth compound semiconductor layer having a smaller thickness than the third compound semiconductor layer on a portion of the second compound semiconductor layer between the second and third electrodes, and a second gate electrode on the fourth compound semiconductor layer. The first compound semiconductor layer between the second and third electrodes includes a 2-dimensional electron gas (2DEG) and the third compound semiconductor layer includes a 2-dimensional hole gas (2DHG).

Abstract: Provided are high electron mobility transistors (HEMTs), methods of manufacturing the HEMTs, and electronic devices including the HEMTs. An HEMT may include an impurity containing layer, a partial region of which is selectively activated. The activated region of the impurity containing layer may be used as a depletion forming element. Non-activated regions may be disposed at opposite side of the activated region in the impurity containing layer. A hydrogen content of the activated region may be lower than the hydrogen content of the non-activated region. In another example embodiment, an HEMT may include a depletion forming element that includes a plurality of regions, and properties (e.g., doping concentrations) of the plurality of regions may be changed in a horizontal direction.

Abstract: A semiconductor device may include a substrate having a drift region doped to a first conduction type. A trench may be etched into an upper surface of the substrate. A gate may be arranged along side walls of the trench. A gate oxide layer may be between the side walls of the trench and gate and between a bottom surface of the trench and gate. A first source region of the first conduction type may be on the upper surface of the substrate. A second source region of the first conduction type may be on the bottom surface of the trench. A first well region may be between the first source region and drift region, and a second well region may be between the second source region and drift region, the first and second well regions being doped to a second conduction type (electrically opposite to the first conduction type).

Abstract: A high side gate driver, a switching chip, and a power device, which respectively include a protection device, are provided. The high side gate driver includes a first terminal configured to receive a first low level driving power supply that is provided to turn off the high side normally-on switch; a first switching device connected to the first terminal; and a protection device connected in series between the first switching device and a gate of the high side normally-on switch, the protection device configured to absorb a majority of a voltage applied to a gate of the high side normally-on switch. The power device includes the high side gate driver. In addition, the switching chip includes a high side normally-on switch, an additional normally-on switch, and a low side normally-on switch, which have a same structure.

Abstract: According to example embodiments, a high electron mobility transistor includes: a channel layer including a first semiconductor material; a channel supply layer on the channel layer and configured to generate a 2-dimensional electron gas (2DEG) in the channel layer, the channel supply layer including a second semiconductor material; source and drain electrodes spaced apart from each other on the channel layer, and an upper surface of the channel supply layer defining a gate electrode receiving part; a first gate electrode; and at least one second gate electrode spaced apart from the first gate electrode and in the gate electrode receiving part. The first gate electrode may be in the gate electrode receiving part and between the source electrode and the drain electrode. The at least one second gate electrode may be between the source electrode and the first gate electrode.

Abstract: A semiconductor device includes a drift layer including a trench formed on a semiconductor substrate. A well in the drift layer overlaps an edge of the trench, and at least one gate electrode is formed at this overlapping edge region. The drift layer and semiconductor may be doped with a first type of impurity and the well may be doped with a second type of impurity. Through this arrangement, an improved distribution of carriers may be formed in the drift layer.

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: Image sensors and methods of operating the same. An image sensor includes a pixel array including a plurality of pixels. Each of the plurality of pixels includes a photo sensor, the voltage-current characteristics of which vary according to energy of incident light, and that generates a sense current determined by the energy of the incident light; a reset unit that is activated to generate a reference current, according to a reset signal for resetting at least one of the plurality of pixels; and a conversion unit that converts the sense current and the reference current into a sense voltage and a reference voltage, respectively.