This invention discloses a metal oxide semiconductor field effect transistor (MOSFET) device. The MOSFET device has a semiconductor substrate that supports an epitaxial layer thereon. The epitaxial layer comprises at least three layers of different dopant concentrations and wherein a middle epitaxial layer having a varying dopant concentration profile along an upward vertical direction.

A semiconductor device with improved performance. A channel region and a well region having a lower impurity concentration than the channel region are formed in a semiconductor substrate on the source region side of an LDMOS. The channel region partially overlaps a gate electrode in plan view. In the gate length direction of the LDMOS, an end of the well region in the channel region is at a distance from the end of the gate electrode on the source region side of the LDMOS in a manner to be away from the gate electrode.

A method of forming a semiconductor device includes forming a gate dielectric layer on a substrate; forming a barrier layer over the gate dielectric layer; treating the barrier layer to roughen an outer surface of the barrier layer, resulting in a treated barrier layer; and forming a metal layer over the treated barrier layer.

A semiconductor device including an isolation insulating film having a first thickness that is located between a drain region and a source region; a gate electrode formed over a region located between the isolation insulating film and the source region and that includes a part serving as a channel; an interlayer insulating film formed so as to cover the gate electrode; and a contact plug formed to reach the inside of the isolation insulating film while penetrating the interlayer insulating film, wherein the contact plug includes a buried part that is formed from the surface of the isolation insulating film up to a depth corresponding to a second thickness thinner than the first thickness.

A semiconductor device includes a semiconductor body having opposite first and second surfaces. The semiconductor device further includes a transistor structure in the semiconductor body and a source contact structure overlapping the transistor structure. The source contact structure is electrically connected to source regions of the transistor structure. A gate contact structure is further provided, which has a part separated from the source contact structure by a longitudinal gap within a lateral plane. Gate interconnecting structures bridge the longitudinal gap and are electrically coupled between the gate contact structure and a gate electrode of the transistor structure. Electrostatic discharge protection structures bridge the longitudinal gap and are electrically coupled between the gate contact structure and the source contact structure. At least one of the gate interconnecting structures is between two of the electrostatic discharge protection structures along a length direction of the longitudinal gap.

A diode includes a semiconductor substrate; a top surface electrode in contact with a part of the top surface of the semiconductor substrate; and a bottom surface electrode in contact with at least a part of the bottom surface of the semiconductor substrate. The semiconductor substrate includes: an n-type high-concentration layer in ohmic contact with the bottom surface electrode; an n-type intermediate-concentration layer on a part of the n-type high-concentration layer; and an n-type low-concentration layer on a part of the n-type high-concentration layer. The n-type low-concentration layer surrounds the n-type intermediate-concentration layer. The top surface electrode is in Schottky contact with a top surface of the n-type intermediate-concentration layer, and a contact region where the top surface electrode and the semiconductor substrate are in contact extends onto then-type low-concentration layer beyond the n-type intermediate-concentration layer.

In one general aspect, a power device can include a first Field Stop (FS) layer of a first conductivity type formed from a first-conductive-type semiconductor substrate. The first FS layer can include a first region having a constant impurity density profile along a depth direction and a second region having an impurity density profile along the depth direction lower than the impurity density profile of the first region. The power device can include a second FS layer of the first conductivity type disposed on a first surface of the first FS layer. The second FS layer can include a first implanted FS layer having an impurity density higher than an impurity density of the first FS layer, and a second implanted FS layer having an impurity density lower than the first implanted FS layer. The second implanted FS layer can be disposed between the first FS layer and the first implanted FS layer. The power device can include a transistor device having components disposed on the second FS layer.

In a semiconductor device that uses an N-channel MOS transistor as an electrostatic protection element, the N-channel MOS transistor has a plurality of electric field relaxing areas, three of which have in a longitudinal direction three different impurity concentrations decreasing from an N-type high concentration drain region downward, and three of which have in a lateral direction three different impurity concentrations decreasing from the N-type high concentration drain region toward a channel region. An electric field relaxing area that is in contact with the electric field relaxing areas in the longitudinal direction and with the electric field relaxing areas in the lateral direction has the lowest impurity concentration.

Field-effect transistor structures for a laterally-diffused metal-oxide-semiconductor (LDMOS) device and methods of forming a LDMOS device. First and second fins are formed that extend vertically from a top surface of a substrate. A first isolation region is arranged between the first fin and the second fin. A body region of a first conductivity type is arranged partially in the substrate and partially in the second fin. A drain region of a second conductivity type is arranged partially in the substrate, partially in the first fin, and partially in the second fin. A source region is arranged within the body region in the first fin. A gate structure is arranged to overlap with a portion of the first fin. A second isolation region is arranged within the first fin, and is spaced along the first fin from the first isolation region.

High-voltage semiconductor devices are provided. The high-voltage semiconductor device includes a substrate having a first conductive type and an epitaxial layer having a second conductive type disposed on the substrate. The epitaxial layer includes a high-voltage unit, a low-voltage unit disposed around the high-voltage unit and a level-shift unit disposed between the high-voltage unit and the low-voltage unit. The level-shift unit includes a source region, a drain region having disposed between the source region and the high-voltage unit, wherein the drain region is electrically connected to the high-voltage unit by a drain electrode disposed above the drain region. The level unit includes a gate electrode disposed between the source region and the drain region. The high-voltage semiconductor device also includes an isolation structure disposed between the high-voltage unit and the low-voltage unit, and the isolation structure is disposed directly under the drain electrode.