A semiconductor device is provided that maintains assembly and improves stress tolerance. The semiconductor device includes a plurality of trenches, a plurality of trench electrodes, an insulation film, and a first electrode. The trench electrodes are provided respectively inside the trenches. The insulation film covers two or more of the trench electrodes. The first electrode is provided on the insulation film. The insulation film has an opening provided between the two or more trench electrodes covered with the insulation film. The first electrode is provided on the semiconductor substrate to fill the opening. Each of the trench electrodes has an upper surface that includes a first recessed portion. The insulation film has an upper surface that includes a second recessed portion located immediately above the first recessed portion. The first electrode has an upper surface that includes a third recessed portion located immediately above the opening.

A method of forming a layered, high power vertical insulated-gate switch uses an n-type substrate. A p-well is formed by implantation in the top surface of the substrate followed by implanting n-type dopants in the p-well to form n+ source regions. Trenched gates are formed extending through the n+ source regions and into the p-well. The wafer is transferred to a carrier and the bottom surface of the wafer substrate is thinned by CMP. An n-buffer layer is then epitaxially grown on the bottom surface using low temperature epitaxy (LTE). The low temperature does not substantially diffuse the dopants in the overlying regions. A bottom p+ layer is then formed by LTE. Anode and cathode metal electrodes are then formed. The n-buffer layer and p+ layers can be precisely formed for optimal efficiency and the LTE maintains the dopant profiles of the overlying regions.

A p-type semiconductor region is formed in a front surface side of an n-type semiconductor substrate. An n-type field stop (FS) region including protons as a donor is formed in a rear surface side of the semiconductor substrate. A concentration distribution of the donors in the FS region include first, second, third and fourth peaks in order from a front surface to the rear surface. Each of the peaks has a peak maximum point, and peak end points formed at both sides of the peak maximum point. The peak maximum points of the first and second peaks are higher than the peak maximum point of the third peak. The peak maximum point of the third peak is lower than the peak maximum point of the fourth peak.

A semiconductor device is an IGBT of a trench-gate structure and has a storage region directly beneath a p.sup.-type base region. The semiconductor device has gate trenches and dummy trenches as trenches configuring the trench-gate structure. An interval (mesa width) at which the trenches are disposed is in a range of 0.7 m to 2 m. In each of the gate trenches, a gate electrode of a gate potential is provided via a first gate insulating film. In each of the dummy trenches, a dummy gate electrode of an emitter potential is provided via a second gate insulating film. A total number of the gate electrode is in a range of 60% to 84% of a total number of the dummy electrodes.

A semiconductor device includes a first region in which a drift, base, and accumulation regions are stacked. Transistor cells are each provided partially in the first region and include at least one trench extending into the drift region. A second region includes a well region provided on an edge termination region side surrounding the first region. A third region of a predetermined width is between the first and second regions, inside of which the transistor cells are partially provided. A bottom region is provided in the first region, adjacent to a bottom of the trench, and between the accumulation and drift regions, the bottom region not extending into the third region, its upper surface located below the base region's lower surface; and first and second electrodes configured to flow current therebetween. The bottom region is spaced apart from the base region by the accumulation region in the depth direction.

A semiconductor device including an IGBT with improved switching characteristics is provided. Inside trenches formed inside a semiconductor substrate of an active cell, a trench gate electrode and a trench emitter electrode are formed through a gate insulating film. An n-type hole barrier region is formed inside the semiconductor substrate located between the trenches. A p-type base region is formed inside the hole barrier region. An n-type emitter region is formed inside the base region. A p-type floating region is formed inside the semiconductor substrate of an inactive cell. A depth of the floating region is shallower than each depth of the trenches, and is deeper than a depth of the base region.

A termination region of an IGBT is described, in which surface p-rings are combined with oxide/polysilicon-filled trenches, buried p-rings and surface field plates, so as to obtain an improved distribution of potential field lines in the termination region. The combination of surface ring termination and deep ring termination offers a significant reduction in the amount silicon area which is required for the termination region.

A method of producing a semiconductor device includes providing a semiconductor body having a front side 10-1 and a back side, wherein the semiconductor body includes a drift region having dopants of a first conductivity type and a body region having dopants of a second conductivity type complementary to the first conductivity type, a transition between the drift region and the body region forming a pn-junction. The method further comprises: creating a contact groove in the semiconductor body, the contact groove extending into the body region along a vertical direction pointing from the front side to the back side; and filling the contact groove at least partially by epitaxially growing a semiconductor material within the contact groove, wherein the semiconductor material has dopants of the second conductivity type.

A method of processing a semiconductor device is presented. The method includes providing a semiconductor body; forming a trench within the semiconductor body, the trench having a stripe configuration and extending laterally within an active region of the semiconductor body that is surrounded by a non-active region of the semiconductor body; forming, within the trench, a first electrode and a first insulator insulating the first electrode from the semiconductor body; carrying out a first etching step for partially removing the first electrode along the total lateral extension of the first electrode such that the remaining part of the first electrode has a planar surface, thereby creating a well in the trench that is laterally confined by the first insulator; depositing a second insulator on top the planar surface; and forming a second electrode within the well of the trench. The second insulator insulates the second electrode from the first electrode.

A power semiconductor transistor includes a semiconductor body coupled to a load terminal, a drift region, a first trench extending into the semiconductor body and including a control electrode electrically insulated from the semiconductor body by an insulator, a source region arranged laterally adjacent to a sidewall of the first trench and electrically connected to the load terminal, a channel region arranged laterally adjacent to the same trench sidewall as the source region, a second trench extending into the semiconductor body, and a guidance zone electrically connected to the load terminal and extending deeper into the semiconductor body than the first trench. The guidance zone is adjacent the opposite sidewall of the first trench as the source region and adjacent one sidewall of the second trench. In a section arranged deeper than the bottom of the first trench, the guidance zone extends laterally towards the channel region.