Abstract: A high voltage ESD protective diode having high avalanche withstand capability and capable of being formed by using manufacturing steps identical with those for a high voltage transistor to be protected, the device having a structure in which a gate oxide film is formed over a substrate surface at a PN junction formed of an N type low concentration semiconductor substrate constituting a cathode region and a P type low concentration diffusion region constituting an anode region, and a gate electrode which is disposed overriding the gate oxide film and a field oxide film is connected electrically by way of a gate plug with an anode electrode, whereby an electric field at the PN junction is moderated upon avalanche breakdown to obtain a high avalanche withstand capability. Further, the withstand voltage can be adjusted by changing the length of the field oxide film.

Abstract: There is provided a high withstand voltage LDMOS which is a MOS transistor formed on a semiconductor substrate and isolated by a trench, and a source region of which is sandwiched by a drain region, in which the metal layer gate wire connected to the gate electrode is led out outside the trench so as to pass over a P-type drift layer.

Abstract: The cell size is reduced and device reliability is improved for a semiconductor device including plural transistors making up a multi-channel output circuit. In a multi-channel circuit configuration, a group of transistors having a common function of plural channels are surrounded by a common trench for insulated isolation from another group of transistors having another function. The collectors of mutually adjacent transistors on the high side are commonly connected to a VH power supply, whereas the emitters of mutually adjacent transistors on the low side are commonly connected to a GND power supply.