A transistor includes a semiconductor body; a body region of a first conductivity type formed in the semiconductor body; a gate electrode formed partially overlapping the body region and insulated from the semiconductor body by a gate dielectric layer; a source region of a second conductivity type formed in the body region on a first side of the gate electrode; a trench formed in the semiconductor body on a second side of the gate electrode, the trench being lined with a sidewall dielectric layer and filled with a bottom dielectric layer and a conductive layer above the bottom dielectric layer, the conductive layer being electrically connected to the gate electrode; and a doped sidewall region of the second conductivity type formed in the semiconductor body along the sidewall of the trench where the doped sidewall region forms a vertical drain current path for the transistor.

The disclosed technology relates to semiconductors, and more particularly to a junction field effect transistor (JFET). In one aspect, a method of fabricating a JFET includes forming a well of a first dopant type in a substrate, wherein the well is isolated from the substrate by an isolation region of a second dopant type. The method additionally includes implanting a dopant of the second dopant type at a surface of the well to form a source, a drain and a channel of the JFET, and implanting a dopant of the first dopant type at the surface of the well to form a gate of the JFET. The method additionally includes, prior to implanting the dopant of the first type and the dopant of the second type, forming a pre-metal dielectric (PMD) layer on the well and forming contact openings in the PMD layer above the source, the drain and the gate. The PMD layer has a thickness such that the channel is formed by implanting the dopant of the first type and the dopant of the second type through the PMD layer. The method further includes, after implanting the dopant of the first type and the dopant of the second type, siliciding the source, the drain and the gate, and forming metal contacts in the contact openings.

The present disclosure provides a method for forming a semiconductor structure. The method includes providing a semiconductor substrate; forming a first active region, a second active region, a third active region, and a fourth active region in the semiconductor substrate; and forming a middle-voltage P well region (MVPW) in each of the first active region and the second region simultaneously and forming a middle-voltage N well (MVNW) region in each of the third active region and the fourth active region simultaneously.

An integrated circuit (IC) includes a first circuit, a first well and a second circuit. The first circuit is disposed on a substrate and configured to shift a first bit signal between a first voltage logic level and a second logic voltage level. The first well is disposed in a cell on the substrate and biased to a first voltage. The first well is spaced apart from a first edge of the cell. The second well is disposed in the cell and biased to a second voltage. The second well is disposed to contact a second edge of the cell opposite to the first edge. The first circuit includes a plurality of transistors respectively disposed in the first and second wells.

In one well bias arrangement, no well bias voltage is applied to the n-well, and no well bias voltage is applied to the p-well. Because no external well bias voltage is applied, the n-well and the p-well are floating, even during operation of the devices in the n-well and the p-well. In another well bias arrangement, the lowest available voltage is not applied to the p-well, such as a ground voltage, or the voltage applied to the n+-doped source region of the n-type transistor in the p-well. This occurs even during operation of the n-type transistor in the p-well. In yet another well bias arrangement, the highest available voltage is not applied to the n-well, such as a supply voltage, or the voltage applied to the p+-doped source region of the p-type transistor in the n-well. This occurs even during operation of the p-type transistor in the n-well.

A semiconductor device includes a bulk substrate of a first conductivity type, a first semiconductor on insulator (SOI) block in the bulk substrate, a first well of the first conductivity type in the first SOI block, a second well of a second conductivity type in the first SOI block, a first guard ring of the first conductivity type in the first SOI block around at least a portion of a periphery of the first SOI block, and a second guard ring of the second conductivity type in the first SOI block around at least a portion of the periphery of the first SOI block. The first conductivity type is different than the second conductivity type.

A method for forming semiconductor devices includes forming a highly doped region. A stack of alternating layers is formed on the substrate. The stack is patterned to form nanosheet structures. A dummy gate structure is formed over and between the nanosheet structures. An interlevel dielectric layer is formed. The dummy gate structures are removed. SG regions are blocked, and top sheets are removed from the nanosheet structures along the dummy gate trench. A bottommost sheet is released and forms a channel for a field effect transistor device by etching away the highly doped region under the nanosheet structure and layers in contact with the bottommost sheet. A gate structure is formed in and over the dummy gate trench wherein the bottommost sheet forms a device channel for the EG device.

First and second active regions are doped with different types of impurities, and extend in a first direction and spaced apart from each other in a second direction. First and third gate structures, which are on the first active region and a first portion of the isolation layer between the first and second active regions, extend in the second direction and are spaced apart from each other in the first direction. Second and fourth gate structures, which are on the second active region and the first portion, extend in the second direction, are spaced apart from each other in the first direction, and face and are spaced apart from the first and third gate structures, respectively, in the second direction. First to fourth contacts are on portions of the first to fourth gate structures, respectively. The first and fourth contacts are connected, and the second and third contacts are connected.

A semiconductor device aims to prevent a leak current from flowing between a well and a corner of an active region formed on an upper surface of another well in an SRAM. In a memory cell of the SRAM, a load MOSFET is formed. An end of an active region extending in y-direction is arranged to gradually go away from a p-well as it goes from a gate electrode G2 side to a gate electrode G4 side in such a manner that a distance in x-direction between the end of the active region and the p-well is larger than a shortest distance in the x-direction between the p-well and the active region.

In a semiconductor integrated circuit device, a plurality of electrode pads for external connection are arranged in a zigzag pattern. Some electrode pads of the electrode pads of the plurality of I/O cells which are closer to a side of the semiconductor chip, each have an end portion closer to the side of the semiconductor chip, the end portion being set at the same position as that of an end portion of the corresponding I/O cell. A power source-side protective circuit and a ground-side protective circuit against discharge of static electricity are provided with the power source-side protective circuit being closer to the scribe region. A distance between a center position of one of the electrode pads and the ground-side protective circuit of the corresponding I/O cell and a distance between a center position of the other one electrode pad and the ground-side protective circuit of the corresponding I/O cell are both short and are substantially equal between each I/O cell.