An integrated enhancement/depletion mode high electron mobility transistor (HEMT) includes a substrate, a first buffer layer, a first barrier layer, a first channel layer, a first source, a first drain, a first gate, a second buffer layer, a second barrier layer, a second channel layer, a second source, a second drain, and a second gate. The first buffer layer is on the substrate. The first barrier layer is on a first area of the first buffer layer, the first channel layer is on the first barrier layer, and the first source, the first drain, and the first gate are on the first channel layer. The second buffer layer is on a second area of the first buffer layer, the second bather layer is on the second buffer layer, the second channel layer is on the second barrier layer, and the second source, the second drain, and the second gate are on the second channel layer.

According to one embodiment, a semiconductor device includes first, and second conductive members, first, second, and third semiconductor regions, and an insulating part. A direction from the first conductive member toward the second conductive member is along a first direction. The first semiconductor region includes first and second partial regions. A second direction from the first partial region toward the second partial region crosses the first direction. The first conductive member is between the first partial region and the second conductive member. A direction from the second partial region toward the second semiconductor region is along the first direction. A direction from the second conductive member toward the second semiconductor region is along the second direction. The third semiconductor region is between the second partial region and the second semiconductor region. The insulating part includes a first insulating region, a second insulating region, and a third insulating region.

A semiconductor device includes a semiconductor layer having a first doped region, a second doped region, and a third doped region. Each of the regions has the same dopant type. The first doped region extends further into a thickness of the semiconductor layer than the second or third doped regions, and the third doped region provides a conductive pathway between the first doped region and the second doped region. The semiconductor device also includes a first transistor and a second transistor. The first doped region is beneath the first transistor and the second doped region is beneath the second transistor. By using a commonly doped well region that includes each of the first, second, and third doped regions, at least the first and second transistors can be integrated closer together which lowers the overall device footprint. The transistors may be FETs, or other transistor technology.

An object is to reduce leakage current and parasitic capacitance of a transistor used for an LSI, a CPU, or a memory. A semiconductor integrated circuit such as an LSI, a CPU, or a memory is manufactured using a thin film transistor in which a channel formation region is formed using an oxide semiconductor which becomes an intrinsic or substantially intrinsic semiconductor by removing impurities which serve as electron donors (donors) from the oxide semiconductor and has larger energy gap than that of a silicon semiconductor. With use of a thin film transistor using a highly purified oxide semiconductor layer with sufficiently reduced hydrogen concentration, a semiconductor device with low power consumption due to leakage current can be realized.

A half bridge circuit is disclosed. The half bridge circuit includes a low side transistor having a low side transistor gate, where a low side transistor gate voltage at the low side transistor gate is controlled by a low side gate signal. The half bridge circuit also includes a high side transistor having a high side transistor gate, where a high side transistor gate voltage at the high side transistor gate is controlled by a high side gate signal. The half bridge circuit also includes a semiconductor circuit configured to allow current to flow from a ground referenced power supply node to a first floating power supply terminal. The semiconductor circuit includes a first transistor, where a gate voltage is controlled by a gate drive circuit control signal, a source is connected to the ground referenced power supply node, and a drain connected to the first floating power supply terminal.

A semiconductor device is made by: forming a metal film containing Al on a surface of a substrate product including a substrate and a nitride semiconductor layer on the substrate, the metal film covering a via hole forming predetermined region, and the surface of the substrate product being located on the nitride semiconductor layer side, forming an etching mask having an opening for exposing the via hole forming predetermined region on a back surface of the substrate product, the back surface of the substrate product being located on the substrate side, and forming a via hole in the substrate product by reactive ion etching, the via hole reaching the surface from the back surface and exposing the metal film. In the forming of the via hole, a reaction gas containing fluorine is used during a period at least including a termination of etching.

Apparatus and circuits including transistors with different threshold voltages and methods of fabricating the same are disclosed. In one example, a semiconductor structure is disclosed. The semiconductor structure includes: a substrate; an active layer that is formed over the substrate and comprises a plurality of active portions; a polarization modulation layer comprising a plurality of polarization modulation portions each of which is disposed on a corresponding one of the plurality of active portions; and a plurality of transistors each of which comprises a source region, a drain region, and a gate structure formed on a corresponding one of the plurality of polarization modulation portions. The transistors have at least three different threshold voltages.

A semiconductor device includes etch stop films formed on the first gate electrode, the first source region, the first drain region, and the shallow trench isolation regions, respectively. First interlayer insulating films are formed on the etch stop film, respectively. Deep trenches are formed in the substrate between adjacent ones of the first interlayer insulating films to overlap the shallow trench isolation regions. Sidewall insulating films are formed in the deep trenches, respectively. A gap-fill insulating film is formed on the sidewall insulating film. A second interlayer insulating film is formed on the gap-fill insulating film. A top surface of the second interlayer insulating film is substantially planar and a bottom surface of the second interlayer insulating film is undulating.

A semiconductor device containing an enhancement mode GaN FET on a III-N layer stack includes a low-doped GaN layer, a barrier layer including aluminum over the low-doped GaN layer, a stressor layer including indium over the barrier layer, and a cap layer including aluminum over the stressor layer. A gate recess extends through the cap layer and the stressor layer, but not through the barrier layer. The semiconductor device is formed by forming the barrier layer with a high temperature MOCVD process, forming the stressor layer with a low temperature MOCVD process and forming the cap layer with a low temperature MOCVD process. The gate recess is formed by a two-step etch process including a first etch step to remove the cap layer, and a second etch step to remove the stressor layer.

A transistor module including a first transistor and a second transistor for start up control is provided. Wherein the first end of the first transistor is coupled to the first end of the second transistor, the second end of the first transistor is coupled to the control end of the second transistor, and the second end of the second transistor provides a start up current for a control circuit.