A semiconductor device includes: a silicon substrate that includes a high-concentration layer containing first conductivity type impurities; a low-concentration layer formed on the high-concentration layer and containing first conductivity type impurities; a first electrode and a second electrode formed on the low-concentration layer; a vertical semiconductor element that allows current to flow between the second electrode and the high-concentration layer; and a first trench unit that realizes electric connection between the first electrode and the high-concentration layer. The first trench unit consists of first polysilicon containing first conductivity type impurities, and a diffusion layer configured to surround the first polysilicon in a plan view and to contain first conductivity type impurities. The first polysilicon is configured to reach the high-concentration layer by penetrating the low-concentration layer. Respective concentrations of the first conductivity type impurities contained in the first polysilicon and in the diffusion layer are kept constant in a direction from the low-concentration layer to the high-concentration layer.

A two-transistor memory cell based upon a thyristor for an SRAM integrated circuit is described together with a process for fabricating it. The memory cell can be implemented in different combinations of MOS and bipolar select transistors, or without select transistors, with thyristors in a semiconductor substrate with shallow trench isolation. Standard CMOS process technology can be used to manufacture the SRAM.

A semiconductor device and manufacturing method achieve miniaturization, prevent rise in threshold voltage and on-state voltage, and prevent decrease in breakdown resistance. N.sup.+-type emitter region and p.sup.++-type contact region are repeatedly alternately disposed in a first direction in which a trench extends in stripe form in a mesa portion sandwiched between trench gates. P.sup.+-type region covers an end portion on lower side of junction interface between n.sup.+-type emitter region and p.sup.++-type contact region. Formation of trench gate structure is such that n.sup.+-type emitter region is selectively formed at predetermined intervals in the first direction in the mesa portion by first ion implantation. P.sup.+-type region is formed less deeply than n.sup.+-type emitter region in the entire mesa portion by second ion implantation. The p.sup.++-type contact region is selectively formed inside the p+-type region by third ion implantation. N.sup.+-type emitter region and p.sup.++-type contact region are diffused and brought into contact.

A method of manufacturing a structure in a semiconductor body comprises forming a first mask above a first surface of the semiconductor body. The first mask comprises an opening surrounding a first portion of the first mask, thereby separating the first portion and a second portion of the first mask. The semiconductor body is processed through the opening at the first surface. The opening is increased by removing at least part of the first mask in the first portion while maintaining the first mask in the second portion. The semiconductor body is further processed through the opening at the first surface.

A semiconductor device of the present invention includes a semiconductor layer, a plurality of gate trenches formed in the semiconductor layer, a gate electrode filled via a gate insulating film in the plurality of gate trenches, an n.sup.+-type emitter region, a p-type base region, and an n.sup.-type drift region disposed, lateral to each gate trench, in order in a depth direction of the gate trench from a front surface side of the semiconductor layer, a p.sup.+-type collector region disposed on a back surface side of the semiconductor layer with respect to the n.sup.-type drift region, an emitter trench formed between the plurality of gate trenches adjacent to each other, and a buried electrode filled via an insulating film in the emitter trench, and electrically connected with the n.sup.+-type emitter region, and the emitter trench is disposed at an interval of 2 m or less via an n.sup.-type drift region with the gate trench.

A method of producing a semiconductor device is disclosed in which, after proton implantation is performed, a hydrogen-induced donor is formed by a furnace annealing process to form an n-type field stop layer. A disorder generated in a proton passage region is reduced by a laser annealing process to form an n-type disorder reduction region. As such, the n-type field stop layer and the n-type disorder reduction region are formed by the proton implantation. Therefore, it is possible to provide a stable and inexpensive semiconductor device which has low conduction resistance and can improve electrical characteristics, such as a leakage current, and a method for producing the semiconductor device.

A diode-connected bipolar junction transistor includes a common collector region of a first conductivity, a common base region of a second conductivity disposed over the common collector region, and a plurality of emitter regions of the first conductivity disposed over the common base region, arranged to be spaced apart from each other, and arranged to have island shapes. The common base region and the common collector region are electrically coupled to each other.

A semiconductor device includes a semiconductor substrate, a base region formed in the semiconductor substrate on a front surface side thereof, a gate trench extending from a front surface side of the base region and penetrating thorough the base region, and a dummy trench extending from the front surface side of the base region and penetrating thorough the base region, where a portion of the dummy trench that extends beyond a back surface of the base region is longer than a portion of the gate trench that extends beyond the back surface of the base region.

The present disclosure relates to semiconductor structures and, more particularly, to a bipolar transistor with a stepped emitter and methods of manufacture. The structure includes: a collector; a base over the collector; and an emitter over the base, the emitter comprising at least one stepped feature over the base.

A three terminal high voltage Darlington bipolar transistor power switching device includes two high voltage bipolar transistors, with collectors connected together serving as the collector terminal. The base of the first high voltage bipolar transistor serves as the base terminal. The emitter of the first high voltage bipolar transistor connects to the base of the second high voltage bipolar transistor (inner base), and the emitter of the second high voltage bipolar transistor serves as the emitter terminal. A diode has its anode connected to the inner base (emitter of the first high voltage bipolar transistor, or base of the second high voltage bipolar transistor), and its cathode connected to the base terminal. Similarly, a three terminal hybrid MOSFET/bipolar high voltage switching device can be formed by replacing the first high voltage bipolar transistor of the previous switching device by a high voltage MOSFET.