Integrated injection logic having high inverse current gain
AssigneeTexas Instruments Incorporated
InventorsWalter T. Matzen, Wilton L. Workman
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Abstract
An integrated injection logic (IIL) structure including active devices, one of which is a switching transistor having base current injection from another active device where an epitaxial zone forms an emitter-base junction. A diffused zone in the epitaxial layer forms a collector for the switching transistor and an insulating structure defines perimeters of the collector-base junction and the emitter-base junction such that the widths thereof are about equal for maximizing current gain with minimal temperature dependence.
Claims6
A fanout logic system which comprises:
- a. a heavily doped first conductivity type semiconductor substrate having a second conductivity type epitaxial layer formed on one surface thereof,
- b. a wide bipolar transistor formed in said epitaxial layer with the epitaxial layer forming the collector of said transistor,
- c. a pair of isolation zones extending from the surface of said epitaxial layer through the lower boundary thereof and extending laterally from the base of said transistor to isolate a portion of said epitaxial layer,
- d. heavily doped first conductivity type regions between the ends of said isolation zones opposite said wide bipolar transistor, said regions extending through said epitaxial layer, and
- e. a plurality of diffused collectors in said epitaxial layer within said zones to form a multiple-collector bipolar transistor, complementary to said wide bipolar transistor with said epitaxial layer forming the common base region thereof, with the base-emmiter junction width equalling the base-collector junction width and wherein said epitaxial layer forming the collector of said wide bipolar transistor also forms the base of said multiple collector bipolar transistor.
An integrated circuit semiconductor logic fanout unit which comprises:
- a. an N+ semiconductor substrate having a P type epitaxial layer on one surface thereof,
- b. a wide PNP transistor formed in said layer with base and emitter terminals at the surface of said layer,
- c. a plurality of pairs of spaced apart insulating structures extending along parallel lines laterally across said structure from the base-collector boundary of said PNP transistor with said structure extending from the surface of said layer through the junction between said layer and the N+ substrate,
- d. N+ regions between the ends of said structures extending through said epitaxial layer to isolate collectors of each array, and
- e. an array of diffused collectors within each of said pair with said collectors of a given array spaced successively greater distances from said PNP transistor with said epitaxial layer forming a common base for said collectors while serving as the collector for said PNP transistor for current injection from said PNP transistor for all said collectors.
Dependencies are inferred from the claim text.