Abstract: A semiconductor device characterized by a field limiting ring formed by a number of field limiting cells that define wells which are laterally diffused to form a continuous equipotential ring between interior and exterior regions of a semiconductor device. A number of active cells are formed in the interior region, and are therefore delineated from the exterior region of the device. Each of these active cells is a transistor, and preferably a field-effect transistor, whose structure is essentially identical to the field limiting cells, except that their wells are not merged but instead are isolated from each other. The field limiting ring increases the breakdown voltage and the ruggedness of device, and therefore enables the device to sustain high voltages when the device is in the off-state. The process does not require masking, implanting and diffusion steps for the sole purpose of forming the field limiting ring, but is instead fully integrated with the semiconductor process for forming the active cells.

Abstract: Region forming steps or interconnect-forming steps through which low voltage CMOS devices are formed in a semiconductor wafer are also employed to simultaneously form one or more regions or layers at selected sites of a substrate where high voltage devices are to be formed. Such selective modification of an already existing mask set designed for low voltage CMOS typography allows additional doping of the substrate or provision of further overlay material to accommodate the effects of high voltage operation of selected areas of the wafer and thereby effectively performs precursor tailoring or modification of those portions of the wafer where a high voltage condition will be encountered.

Abstract: An IGBT chip includes a unit cell region and a guard ring region which surrounds the unit cell region. In the unit cell region, a plurality of IGBT unit cells are formed, each of which comprises a base layer, a source layer, a common gate electrode, a common source electrode, and a common drain electrode. In the guard ring region, at least one diffused layer making up a guard ring is formed. Further, an annular diffused layer is formed and is connected to the drain electrode. The annular diffused layer is disposed away from the outermost guard ring by a specified length. This length is such that the punch-through occurs before the avalanche breakdown voltage of the junction associated with the outermost guard ring. Therefore, the withstand voltage against the avalanche breakdown when surge voltage is applied to the drain electrode is improved.

Abstract: A semiconductor device for influencing the breakdown voltage of a transistor with a surface electrode arranged over a space charge region, separated from the same by an oxide layer. The surface electrode is at a potential, as determined by a voltage divider, between the potentials of the base and collector of the transistor. The surface electrode includes two electrode plates insulated from one another, with the first electrode plate extending over a junction between a highly doped n.sup.+ collector region and a lightly doped n.sup.- collector region, and a junction between the lightly doped n.sup.- collector region and a p-type base region. The second electrode plate is bonded partly over the oxide layer and partly with the highly doped n.sup.+ collector region.

Abstract: The present invention relates to a semiconductor device which is fabricated in simple process steps and which prevents deterioration in a breakdown voltage. Two diffusion regions are formed in space in a surface of an n.sup.- type layer. The diffusion regions are separated from each other by an insulation layer, but each in contact with a conductive film. Another conductive film is disposed on the insulation layer. The three conductive films are insulated from each other by the insulation layer and still another overlying insulation layer. Still other conductive films are formed on the upper insulation layer, and are coupled to the three conductive films. A wiring conductive film is also formed on the upper insulation layer. The wiring conductive film has a relatively small capacitance with the three conductive films. Due to the device structure, influence of the wiring conductive film over the surface of the semiconductor device is blocked by the conductive films.

Abstract: A semiconductor device is provided having a substrate which includes a floating circuit well with turn on/turn off signals generated by a voltage drop proximate to at least one resistor contained therein, and having high-voltage interconnects to connect the drain terminals of a plurality of LDMOS transistors to the resistor in the floating well and wherein the transistors, resistor and floating well are combined into an integrated structure which eliminates the high voltage interconnect crossovers.

Abstract: An integrated device includes isolating regions of a first type of conductivity, each surrounding an epitaxial pocket of an opposite type of conductivity, and housing drain and source regions, and covered with an oxide layer housing gate regions and over which extend the source, drain and gate connections. For linearizing potential distribution at the epitaxial pocket-isolating region junction and close to the source regions beneath the connections, these regions are provided with a double chain of condensers embedded in the oxide layer and the terminal elements and the intermediate element of which are biased to predetermined potentials.

Abstract: For a vertical DMOS power transistor or a high voltage bipolar transistor, an edge termination at the perimeter of the die surrounding the active transistor cells includes multiple spaced apart field rings. A trench is located between each adjacent pair of field rings and is insulated either by oxide formed on the sidewalls thereof or by an oxide filling. The insulated trenches allow the field rings to be very closely spaced together. Advantageously the trenches may be formed in the same process steps as are the trenched gate electrodes of the active portion of the transistor. This structure eliminates the necessity for fabricating thick field oxide underlying a conventional field plate termination, and hence allows fabrication of a transistor without the need for a field plate termination, and in which the multiple field rings are suitable for a transistor device having a breakdown voltage in the range of 20 to 150 volts.

Abstract: A power MOSFET with improved avalanche resistance has a cell field in which the lateral cells are provided with source zones which are partly omitted or of a reduced size. The avalanche resistance is further improved in terms of reduced manufacturing cost in that a p-doped annular zone is disposed between the cell field and the edge of the semiconductor body. An annular trench is formed in the annular zone. The annular trench is contacted with the source metallization. The annular zone and the annular trench have the same depth as the gate zones of the cells and/or as the source contact holes.

Abstract: There is disclosed a semiconductor device wherein a p layer (7) is formed in an isolating portion (Z) and portions (1a, 1b) of an n-type base layer (1) lie on opposite sides of the p layer (7), the upper surfaces of the p layer (7) and the portions (1a, 1b) lying in the same plane as the upper surface of a p layer (3). The presence of the p layer (7) provides for high resistance to breakdown and high formation accuracy of the p layers (2, 3, 7) as compared with a structure in which the isolating portion (Z) lies in the bottom of a the recess, whereby the semiconductor device is less susceptible to short-circuit between the p-type base layer (2) and the p layer (3).

Abstract: For manufacturing vertical MOS transistors, doped regions for a drain (11), well (3), and source (4) are formed in a vertical sequence in a substrate (1). Using a Si.sub.3 N.sub.4 mask (5), trenches (6) are etched perpendicular to the surface of the substrate (1). The trenches isolate the source (4) and well (3) structure, and are filled with doped polysilicon and are closed in an upper region with an insulation structure (8) in self-aligned fashion on the basis of local oxidation. The insulation structure (8) projects laterally beyond the trenches (6). Using the insulation structure (8) as an etching mask, via contact holes (9), that are provided with a metallization for contacting the source (4) and the well (3), are opened down into the well (3) between neighboring trenches (6).

Abstract: A semiconductor body (2) has adjacent a first major surface (3) a first region (5) of one conductivity type part of which defines an active device area (6) of a power semiconductor device (7) having at least two electrodes (8 and 9 or 8 and 10) and active device regions (11) each forming with the first region (5) a pn junction (11a) extending to the first major surface (3). A protection device (12) formed by a series-connected array of semiconductor rectifying elements (13) is provided on an insulating layer (14) on the first major surface (3). The protection device (12) is connected between at least two electrodes (8 and 9 or 10) of the power semiconductor device (7) so as to break down to cause conduction between the two electrodes when the voltage across the protection device (12) exceeds a predetermined limit.

Abstract: The junction field effect transistors (JFETs) of this invention have improved breakdown voltage capability, reduced on-resistance and improved overdrive capability. The JFET on-resistance is decreased by ion-implanting an insulating layer covering a layer that contains the source and gate regions of the unipolar transistor. The charge of the implanted ions is the same as the charge polarity of the gate regions. To improve the overdrive capability of a JFET a region of conductivity opposite to the conductivity of the gate region is formed in the gate region of the transistor. This region of opposite conductivity creates another junction within the gate region i.e., the junction between the region of opposite conductivity and the gate region, and the junction between the gate region and the layer containing the gate region.

Abstract: Conductive plates (16a-16e), or floating semiconductor regions (17a-17d), or conductive plates (16a, 16c, 16e) and floating semiconductor regions (17a, 17d) are disposed in alignment so that a coupling capacitance between the conductive plates and/or the floating semiconductor regions which are adjacent to each other decrease as a distance from a first or second semiconductor region (12, 13) increases. Therefore, the respective potentials at the conductive plates or the floating semiconductor regions can be varied linearly (or at equal potential differences), and corresponding potential distribution can be achieved on the surface of a semiconductor substrate (11). As a result, electric field concentration on the surface of the semiconductor substrate (11) just under a high potential conductive layer (14) can be prevented effectively even by the use of an insulating layer (15) with a common thickness.

Abstract: On the p.sup.- substrate, the n.sup.- epitaxial layer is surrounded and isolated by the p well. In the surface of the n.sup.- epitaxial layer, there is provided the p floating region in the vicinity of the p well, on which the sense electrode is provided. The insulation film and the conductive film are formed on the n.sup.- epitaxial layer between the p well and the p floating region to overlap them. The conductive film and the p floating region serve as a composite field plate, which makes it hard that the surface electric field distribution is influenced by the state of electric charge in the surface and relieves the surface electric field by expanding the depletion layer, which extends from the pn junction between the n.sup.- epitaxial layer and the p well into the n.sup.- epitaxial layer in current blocking state, toward the center of the n.sup.- epitaxial layer.

Abstract: A silicon carbide power MOSFET device includes a first silicon carbide layer, epitaxially formed on the silicon carbide substrate of opposite conductivity type. A second silicon carbide layer of the same conductivity type as the substrate is formed on the first silicon carbide layer. A power field effect transistor is formed in the device region of the substrate and in the first and second silicon carbide layers thereover. At least one termination trench is formed in the termination region of the silicon carbide substrate, extending through the first and second silicon carbide layers thereover. The termination trench defines one or more isolated mesas in the termination region which act as floating field rings. The termination trenches are preferably insulator lined and filled with conductive material to form floating field plates. The outermost trench may be a deep trench which extends through the first and second silicon carbide layers and through the drift region of the silicon carbide substrate.

Abstract: A photosensitive device includes a semiconductor body (1) having a first region (2) of one conductivity type adjacent a given surface (3) of the body with a second region (4) of the opposite conductivity type surrounding the first region (2) so as to form with the first region a main pn junction (5) terminating at the given surface (3), the main pn junction (5) being reverse-biassed in operation of the device. One or more further regions (6) of the one conductivity type surround the main pn junction (5) adjacent the given surface (3) so that each further region (6) forms a photosensitive pn junction (17) with the second region (4), the further region(s) (6) lying within the spread of the depletion region of the main pn junction (5) when the main pn junction (5) is reverse-biassed in operation of the device so as to increase the breakdown voltage of the main pn junction (5).

Abstract: There is provided p diffusion regions (18a, 18b) in the surface of an end portion of the n island (7) formed on the p.sup.- substrate (12). The insulation film (14) is formed on the n island (7) to form therein conductive plates (16a-16e). The p diffusion regions (18a, 18b) and the conductive plates (16a-16e) are alternately arranged and so aligned that adjacent pairs of end portions thereof overlap with each other. Capacitances of capacitive coupling of the conductive plates (16a-16e) and the p diffusion regions (18a, 18b) are optimized so that potentials of the conductive plates (16a-16e) and the p diffusion regions (18a, 18b) can substantially linearly change from a low level to a high level. Thus, the concentration of electric field can be prevented.