A problem associated with n-channel power MOSFETs and the like that the following is caused even by relatively slight fluctuation in various process parameters is solved: source-drain breakdown voltage is reduced by breakdown at an end of a p-type body region in proximity to a portion in the vicinity of an annular intermediate region between an active cell region and a chip peripheral portion, arising from electric field concentration in that area. To solve this problem, the following measure is taken in a power semiconductor device having a superjunction structure in the respective drift regions of a first conductivity type of an active cell region, a chip peripheral region, and an intermediate region located therebetween: the width of at least one of column regions of a second conductivity type comprising the superjunction structure in the intermediate region is made larger than the width of the other regions.

A method for eliminating divot formation includes forming an isolation layer; forming a conduction layer which has an upper inclined boundary with the isolation layer such that the conduction layer has a portion located above a portion of the isolation layer at the upper inclined boundary; etching back the isolation layer; and etching back the conduction layer after etching back the isolation layer such that a top surface of the etched conduction layer is located at a level lower than a top surface of the etched isolation layer.

A MOS transistor includes a substrate, a first region, a second region, a source region, a drain region, an active gate stack, and a dummy gate stack. The substrate has a first conductivity. The first region having the first conductivity is formed in the substrate. The second region having a second conductivity is formed in the substrate and is adjacent to the first region. The source region with the second conductivity is formed in the first region. The drain region with the second conductivity is formed in the second region. The active gate stack is disposed on the first region. The dummy gate stack is disposed on the second region, and the dummy gate stack is electrically coupled to a variable voltage.

A semiconductor device includes a transistor in a semiconductor substrate having a first main surface. The transistor includes a source region, a drain region, a channel region, a drift zone, and a gate electrode adjacent to at least two sides of the channel region. The gate electrode is disposed in trenches extending in a first direction parallel to the first main surface. The gate electrode is electrically coupled to a gate terminal. The channel region and the drift zone are disposed along the first direction between the source region and the drain region. The semiconductor device further includes a conductive layer beneath the gate electrode and insulated from the gate electrode. The conductive layer is electrically connected to the gate terminal.

A transistor arrangement includes: a layer stack with first and second semiconductor layers of complementary first and second doping types; a first source region of a first transistor device adjoining the first semiconductor layers; a first drain region of the first transistor device adjoining the second semiconductor layers and spaced apart from the first source region; gate regions of the first transistor device, each gate region adjoining at least one second semiconductor layer, being arranged between the first source region and the first drain region, and being spaced apart from the first source region and the first drain region; a third semiconductor layer adjoining the layer stack and each of the first source region, first drain region, and each gate region; and active regions of a second transistor device integrated in the third semiconductor layer in a second region spaced apart from a first region of the third semiconductor layer.

A method for forming a semiconductor device includes incorporating dopants of a first conductivity type into a nearby body region portion of a semiconductor substrate having a base doping of the first conductivity type. The incorporation of the dopants of the first conductivity type is masked by a mask structure at at least part of an edge region of the semiconductor substrate. The method further includes forming a body region of a transistor structure of a second conductivity type in the semiconductor substrate. The nearby body region portion of the semiconductor substrate is located adjacent to the body region of the transistor structure.

An object of the present invention is to provide a silicon carbide semiconductor device with which the electric field at the time of switching is relaxed and the element withstand voltage can be enhanced. The distance between the outer peripheral end of a second surface electrode and the inner peripheral end of a field insulation film is smaller than the distance between an outer peripheral end of the second surface electrode and an inner peripheral end of the field insulation film in the case where the electric field strength applied to the outer peripheral lower end of the second surface electrode is calculated so as to become equal to the smallest dielectric breakdown strength among the dielectric breakdown strength of the field insulation film and the dielectric breakdown strength of the surface protective film at the time of switching when the value of dV/dt is greater than or equal to 10 kV/μs.

The high-voltage transistor device comprises a semiconductor substrate (1) with a source region (2) of a first type of electrical conductivity, a body region (3) including a channel region (4) of a second type of electrical conductivity opposite to the first type of conductivity, a drift region (5) of the first type of conductivity, and a drain region (6) of the first type of conductivity extending longitudinally in striplike fashion from the channel region (4) to the drain region (6) and laterally confined by isolation regions (9). The drift region (5) comprises a doping of the first type of conductivity and includes an additional region (8) with a net doping of the second type of conductivity to adjust the electrical properties of the drift region (5). The drift region depth and the additional region depth do not exceed the maximal depth (17) of the isolation regions (9).

Aspects of the invention provide a compact semiconductor device having a surge protection element, which can reliably protect against surge and is unlikely to be affected by manufacturing variation. By forming a parasitic n-p-n transistor on a guard ring, and adopting the parasitic n-p-n transistor as a surge protection element, it is possible to provide a compact semiconductor device having a surge protection element. Also, by adopting the parasitic n-p-n transistor as a surge protection element, it is possible to reduce the operating resistance in comparison with when using a parasitic n-p-n transistor as a surge protection element, and thus possible to improve the surge protection function. Further, by providing one surge protection element on the guard ring, rather than providing a surge protection element in each cell, it is possible minimize the effect of manufacturing variation (i.e., in-plane variation) on the surge protection function.

A method includes forming a gate spacer along sidewalls of a gate structure, forming a source region and a drain region on opposite sides of the gate structure, wherein a sidewall of the source region is vertically aligned with a first sidewall of the gate spacer, depositing a dielectric layer over the substrate, depositing a conductive layer over the dielectric layer, patterning the dielectric layer and the conductive layer to form a field plate, wherein the dielectric layer comprises a horizontal portion extending from the second drain/source region to a second sidewall of the gate spacer and a vertical portion formed along the second sidewall of the gate spacer, forming a plurality of metal silicide layers by applying a salicide process to the conductive layer, the gate structure, the first drain/source region and the second drain/source region and forming contact plugs over the plurality of metal silicide layers.