A semiconductor device includes an enhancement mode MOSFET and a junction FET. The MOSFET has a first semiconductor substrate of a first conductivity type, a first first-semiconductor-layer of the first conductivity type, first second-semiconductor-regions of a second conductivity type, first first-semiconductor-regions of the first conductivity type, first gate insulating films, first gate electrodes, a first first-electrode, and a first second-electrode. The FET has a second semiconductor substrate of the first conductivity type, a second first-semiconductor-layer of the first conductivity type, second first-semiconductor-regions of the first conductivity type, a second second-semiconductor-layer of the second conductivity type, second gate electrodes, a second first-electrode, and a second second-electrode. The first second-electrode and the second second-electrode are connected electrically.

A semiconductor device includes: a substrate; a channel layer constituted of a single nitride semiconductor on the substrate; a first barrier layer which is a nitride semiconductor on a part of an upper surface of the channel layer and having a band gap larger than that of the channel layer; a gate layer which is a nitride semiconductor on and in contact with the first barrier layer; a second barrier layer which is a nitride semiconductor in contact with the first barrier layer in an area where the gate layer is not disposed above the channel layer, and having a band gap larger than that of the channel layer and having a thickness or a band gap independent from the first barrier layer; a gate electrode on the gate layer; and a source electrode and a drain electrode spaced apart from the gate layer and on the second barrier layer.

A semiconductor device includes: a substrate; a channel layer constituted of a single nitride semiconductor on the substrate; a first barrier layer which is a nitride semiconductor on a part of an upper surface of the channel layer and having a band gap larger than that of the channel layer; a gate layer which is a nitride semiconductor on and in contact with the first barrier layer; a second barrier layer which is a nitride semiconductor in contact with the first barrier layer in an area where the gate layer is not disposed above the channel layer, and having a band gap larger than that of the channel layer and having a thickness or a band gap independent from the first barrier layer; a gate electrode on the gate layer; and a source electrode and a drain electrode spaced apart from the gate layer and on the second barrier layer.

A semiconductor device with a reduced tail current is provided. The semiconductor device includes a first junction field effect transistor. The first junction field effect transistor includes a drift layer of a first conductivity type, a first source region of the first conductivity type, a first gate region of a second conductivity type, a first drain region of the first conductivity type, a semiconductor region of the second conductivity type, and a control electrode. The first source region is provided in the semiconductor region. The control electrode is electrically connected to the semiconductor region.

A semiconductor device with a reduced tail current is provided. The semiconductor device includes a first junction field effect transistor. The first junction field effect transistor includes a drift layer of a first conductivity type, a first source region of the first conductivity type, a first gate region of a second conductivity type, a first drain region of the first conductivity type, a semiconductor region of the second conductivity type, and a control electrode. The first source region is provided in the semiconductor region. The control electrode is electrically connected to the semiconductor region.

Disclosed is a semiconductor logic element including a field effect transistor of the first conductivity type and a field effect transistor of the second conductivity type. A gate of the first FET is an input of the semiconductor logic element, a drain of the second FET is referred to as the output of the semiconductor logic element and a source of the second FET is the source of the semiconductor logic element. By applying applicable potentials to the terminals of the field effect transistors it is possible to influence the state of the output of the logic element. Also disclosed are different kinds of logic circuitries including the described logic element.

Disclosed is a semiconductor logic element including a field effect transistor of the first conductivity type and a field effect transistor of the second conductivity type. A gate of the first FET is an input of the semiconductor logic element, a drain of the second FET is referred to as the output of the semiconductor logic element and a source of the second FET is the source of the semiconductor logic element. By applying applicable potentials to the terminals of the field effect transistors it is possible to influence the state of the output of the logic element. Also disclosed are different kinds of logic circuitries including the described logic element.

A semiconductor device and a semiconductor structure are disclosed. The semiconductor device includes a substrate, a first III-V compound layer, a second III-V compound layer, a source, a drain and a gate stack structure. The first III-V compound layer is disposed on the substrate. The second III-V compound layer is disposed on the first III-V compound layer. The source and the drain are disposed on opposite sidewall boundaries of the second III-V compound layer. The gate stack structure is disposed on the second III-V compound layer. The gate stack structure includes a first gate and a second gate. The first gate is disposed on the second III-V compound layer. The second gate is disposed on and electrically isolated from the first gate. The second gate is electrically coupled to the source.

A semiconductor device and a semiconductor structure are disclosed. The semiconductor device includes a substrate, a first III-V compound layer, a second III-V compound layer, a source, a drain and a gate stack structure. The first III-V compound layer is disposed on the substrate. The second III-V compound layer is disposed on the first III-V compound layer. The source and the drain are disposed on opposite sidewall boundaries of the second III-V compound layer. The gate stack structure is disposed on the second III-V compound layer. The gate stack structure includes a first gate and a second gate. The first gate is disposed on the second III-V compound layer. The second gate is disposed on and electrically isolated from the first gate. The second gate is electrically coupled to the source.

A method includes forming a deep well region of a first conductivity type in a substrate, implanting a portion of the deep well region to form a first gate, and implanting the deep well region to form a well region. The well region and the first gate are of a second conductivity type opposite the first conductivity type. An implantation is performed to form a channel region of the first conductivity type over the first gate. A portion of the deep well region overlying the channel region is implanted to form a second gate of the second conductivity type. A source/drain implantation is performed to form a source region and a drain region of the first conductivity type on opposite sides of the second gate. The source and drain regions are connected to the channel region, and overlap the channel region and the first gate.