Transistor circuit

Claim 1

A solid state device comprising: a first region of semiconductor material of one semiconductor type; second and third regions of semiconductor material of the opposite semiconductor type forming mutually isolated islands within said first region, said second region being closely spaced from only a portion of the surface area of said third region by a portion of said first region, said portion of said first region having a width less than the diffusion length of minority carriers in said first region, whereby said portion of said first region acts substantially as the base region of a lateral transistor, said second and third regions respectively acting as the collector and emitter thereof; a fourth region of semiconductor material of said one semiconductor type forming an isolated island within said third region, whereby said fourth region acts as the emitter region of a transversal transistor, said third and first regions respectively acting as the base and collector thereof; a further transistor having a base of semiconductor material of said opposite semiconductor type and an emitter and collector of semiconductor material of said one semiconductor type, said base, emitter and collector being electrically connected to said second, fourth and third regions respectively, whereby said lateral transistor is conductive only when said transversal transistor is actually saturated and thereby causes said further transistor to limit saturation of said transversal transistor in response thereto; and means for making electrical connection to said third and fourth regions and to said first region at a location remote from said portion thereof spacing said second and third regions.