A semiconductor arrangement comprising; a normally-on transistor having first and second main terminals and a control terminal, a normally-off transistor having first and second main terminals and a control terminal, the transistors connected in a cascade arrangement by a connection between one of the main terminals of the normally-on transistor and one of the main terminals of the normally-off transistor, a current-source arrangement connected to a node on the connection and configured to provide for control of the voltage at said node between the normally-on and normally-off transistors by providing for a predetermined current flow, wherein the semiconductor arrangement comprises a first semiconductor die of III-V semiconductor type having the normally-on transistor formed therein and a second semiconductor die having the normally-off transistor formed therein, the current-source arrangement formed in the first and/or second semiconductor dies.

A horizontal MOSFET is arranged in parallel to a horizontal MOSFET and a portion of a return current IL which flows to a linear solenoid flows as a current to the horizontal MOSFET. Therefore, a current which flows to a parasitic transistor is reduced and it is possible to suppress the current which flows to the parasitic transistor provided in the horizontal MOSFET. Since the current which flows to the parasitic transistor is reduced, it is possible to prevent the erroneous operation and breakdown of a semiconductor device forming a synchronous rectification circuit.

This invention provides a composite device and a switching power supply. The composite device integrates therein a first enhancement-mode MOS device and a depletion-mode MOS device, and comprises: an epitaxial region of a first doping type; a first well region and a second well region formed in parallel on the front side of the epitaxial region; a first doped region of the first doping type formed within the first well region; a gate of the first enhancement-mode MOS device; a second doped region of the first doping type formed within the second well region; a channel region of the first doping type, wherein the channel region extends from a boundary of the second well region to a boundary of the second doped region; and a gate of the depletion-mode MOS device. The switching power supply includes the composite device above. This invention can decrease the process complexity, reduce the chip area and cost, and may be applicable to high power scenarios.

A semiconductor device includes device isolation layer on a substrate to define an active region, a first gate electrode on the active region extending in a first direction parallel to a top surface of the substrate, a second gate electrode on the device isolation layer and spaced apart from the first gate electrode in the first direction, a gate spacer between the first gate electrode and the second gate electrode, and source/drain regions in the active region at opposite sides of the first gate electrode. The source/drain regions are spaced apart from each other in a second direction that is parallel to the top surface of the substrate and crossing the first direction, and, when viewed in a plan view, the first gate electrode is spaced apart from a boundary between the active region and the device isolation layer.

A method of fabricating an epitaxial stack for Group IIIA-N transistors includes depositing at least one Group IIIA-N buffer layer on a substrate in a deposition chamber of a deposition system. At least one Group IIIA-N cap layer is then deposited on the first Group IIIA-N buffer layer. During a cool down from the deposition temperature for the cap layer deposition the gas mixture supplied to the deposition chamber includes NH.sub.3 and at least one other gas, wherein the gas mixture provide an ambient in the deposition chamber that is non-etching with respect to the cap layer so that at a surface of the cap layer there is (i) a room mean square (rms) roughness of <10 and (ii) a pit density for pits greater than (>) 2 nm deep less than (<) 10 pits per square m with an average pit diameter less than (<) 0.05 m.

A semiconductor device includes a first transistor and a clamping circuit. The first transistor is arranged to generate an output signal according to a control signal. The clamping circuit is arranged to generate the control signal according to an input signal, and to clamp the control signal to a predetermined signal level when the input signal exceeds the predetermined signal level.

A maximum voltage selection circuit may include multiple inputs, each for receiving a different input voltage, an output for delivering the highest of the input voltages, and a voltage selection circuit. The voltage selection circuit may automatically select the input having the largest voltage magnitude, automatically deliver the voltage at the selected input to the output, and not draw quiescent operating current from any of the inputs. For each and every unique combination of two of the multiple inputs, the voltage selection circuit may include an enhancement mode FET with a channel connected in series between a first input of the unique combination of the two inputs and the output; a connection between the gate of the enhancement mode FET and the second input of the unique combination of the two inputs through the channel of a depletion mode FET; an additional enhancement mode FET with a channel connected in series between the second of the unique combination of the two inputs and the output; and a connection between the gate of the additional enhancement mode FET and the first of the unique combination of the two inputs through the channel of an additional depletion mode FET.

A method for manufacturing a semiconductor device having metal gates includes following steps. A substrate including a first transistor and a second transistor formed thereon is provided. The first transistor includes a first gate trench and the second transistor includes a second gate trench. A patterned first work function metal layer is formed in the first gate trench and followed by forming a second sacrificial masking layer respectively in the first gate trench and the second gate trench. An etching process is then performed to form a U-shaped first work function metal layer in the first gate trench. Subsequently, a two-step etching process including a strip step and a wet etching step is performed to remove the second sacrificial masking layer and portions of the U-shaped first work function metal layer to form a taper top on the U-shaped first work function metal layer in the first gate trench.

GaN-based half bridge power conversion circuits employ control, support and logic functions that are monolithically integrated on the same devices as the power transistors. In some embodiments a low side GaN device communicates through one or more level shift circuits with a high side GaN device. Both the high side and the low side devices may have one or more integrated control, support and logic functions. Some devices employ electro-static discharge circuits and features formed within the GaN-based devices to improve the reliability and performance of the half bridge power conversion circuits.

A III-N enhancement-mode transistor includes a III-N structure including a conductive channel, source and drain contacts, and a gate electrode between the source and drain contacts. An insulator layer is over the III-N structure, with a recess formed through the insulator layer in a gate region of the transistor, with the gate electrode at least partially in the recess. The transistor further includes a field plate having a portion between the gate electrode and the drain contact, the field plate being electrically connected to the source contact. The gate electrode includes an extending portion that is outside the recess and extends towards the drain contact. The separation between the conductive channel and the extending portion of the gate electrode is greater than the separation between the conductive channel and the portion of the field plate that is between the gate electrode and the drain contact.