A semiconductor device includes a vertical protection device having a thyristor and a lateral trigger element disposed in a substrate. The lateral trigger element is for triggering the vertical protection device.

Fabrication methods and device structures for a silicon controlled rectifier. A cathode is arranged over a top surface of a substrate and a well is arranged beneath the top surface of the substrate. The cathode is composed of a semiconductor material having a first conductivity type, and the well also has the first conductivity type. A semiconductor layer, which has a second conductivity type opposite to the first conductivity type, includes a section over the top surface of the substrate. The section of the semiconductor layer is arranged to form an anode that adjoins the well along a junction.

A one-way switch has a gate referenced to a main back side electrode. An N-type substrate includes a P-type anode layer covering a back side and a surrounding P-type wall. First and second P-type wells are formed on the front side of the N-type substrate. An N-type cathode region is located in the first P-type well. An N-type gate region is located in the second P-type well. A gate metallization covers both the N-type gate region and a portion of the second P-type well. The second P-type well is separated from the P-type wall by the N-type substrate except at a location of a P-type strip that is formed in the N-type substrate and connects a portion on one side of the second P-type well to an upper portion of said P-type wall.

An electrostatic discharge (ESD) protection device includes a pad, a diode, a gate ground NMOS (GGNMOS) transistor and a thyristor. The diode includes an anode connected with the pad. The GGNMOS transistor is connected between a cathode of the diode and a ground terminal. The thyristor is formed between the diode and the ground terminal when an ESD current may flow from the pad.

A bi-directional semiconductor switching device is formed by forming first and second vertical field effect transistors (FETs) formed in tandem from a semiconductor substrate. A source for the first FET is on a first side of the substrate and a source for the second FET is on a second side of the substrate opposite the first side. Gates for both the first and second. FETs are disposed in tandem in a common set of trenches formed a drift region of the semiconductor substrate that is sandwiched between the sources for the first and second FETs. The drift layer acts as a common drain for both the first FET and second FET.

An electrostatic discharge (ESD) protection device includes a pad, a diode, a gate ground NMOS (GGNMOS) transistor and a thyristor. The diode includes an anode connected with the pad. The GGNMOS transistor is connected between a cathode of the diode and a ground terminal. The thyristor is formed between the diode and the ground terminal when an ESD current may flow from the pad.

A semiconductor integrated circuit includes: an n.sup.-type support layer; a p-type well region provided in an upper portion of the support layer; a p.sup.+-type circuit side buried layer provided inside the well region; an n.sup.+-type first and second terminal regions provided in an upper portion of the well region and above the circuit side buried layer; a p-type body region provided in an upper portion of the support layer; a control electrode structure provided in a gate trench; a p.sup.+-type output side buried layer provided inside the body region so as to be in contact with the control electrode structure; and an n.sup.+-type output terminal region provided in an upper portion of the body region and above the output side buried layer, wherein an output stage element having the output terminal region is controlled by a circuit element including the first and second terminal regions.

A triac has a vertical structure formed from a silicon substrate having an upper surface side. A main metallization on the upper surface side has a first portion resting on a first region of a first conductivity type formed in a layer of a second conductivity type. A second portion of the main metallization rests on a portion of the layer. A gate metallization on the upper surface side rests on a second region of the first conductivity type formed in the layer in the vicinity of the first region. A porous silicon bar formed in the layer at the upper surface side has a first end in contact with the gate metallization and a second end in contact with the main metallization.

A bi-directional semiconductor switching device includes first and second vertical field effect transistors (FETs) formed in tandem from a semiconductor substrate. A source for the first FET is on a first side of the substrate and a source for the second FET is on a second side of the substrate opposite the first side. Gates for both the first and second FETs are disposed in tandem in a common set of trenches formed a drift region of the semiconductor substrate that is sandwiched between the sources for the first and second FETs. The drift layer acts as a common drain for both the first FET and second FET.

A semiconductor device of the present invention achieves improved avoidance of a parasitic operation in a circuit region while achieving miniaturization of the semiconductor device and a reduction in the amount of time for manufacturing the semiconductor device. The semiconductor device according to the present invention includes an IGBT disposed on a first main surface of a semiconductor substrate provided with a drift layer of a first conductivity type; a thyristor disposed on the first main surface of the semiconductor substrate; a circuit region; a hole-current retrieval region separating the IGBT and the circuit region in a plan view; and a diffusion layer of a second conductivity type, the diffusion layer being disposed on a second main surface of the semiconductor substrate. The IGBT has an effective area equal to or less than an effective area of the thyristor in a plan view.