LATERAL BIPOLAR TRANSISTOR

Abstract

A P+ base drawing diffusion region is formed on a substrate having an SOI structure. N+ emitter diffusion regions are formed on both sides of the P+ base drawing diffusion region through isolation insulating films interposed therebetween. A P type SOI layer, which serves as a base diffusion region, is formed so as to surround the N+ emitter diffusion regions, and conductive layers are formed thereon. Further, an N+ collector diffusion region is formed so as to surround the conductive layers.

Description

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plan view of a lateral bipolar transistor according to a first embodiment of the present invention;

FIG. 2 is a sectional view obtained by cutting the lateral bipolar transistor of the first embodiment of the present invention along X-X′ plane shown in FIG. 1;

FIG. 3 is a sectional view obtained by cutting the lateral bipolar transistor of the first embodiment of the present invention along Y-Y′ plane shown in FIG. 1;

FIGS. 4 through 8 are diagrams for describing a fabricating method of the lateral bipolar transistor of the first embodiment of the present invention;

FIG. 9 is a plan view of a lateral bipolar transistor showing a comparative example;

FIG. 10 is a sectional view obtained by cutting the lateral bipolar transistor of the comparative example along X-X′ plane shown in FIG. 9;

FIG. 11 is a plan view of a lateral bipolar transistor which is a modification of the first embodiment of the present invention;

FIG. 12 is a plan view of a lateral bipolar transistor showing a second embodiment of the present invention;

FIG. 13 is a plan view of a lateral bipolar transistor according to a third embodiment of the present invention;

FIG. 14 is a sectional view obtained by cutting the lateral bipolar transistor according to the third embodiment of the present invention along X-X′ plane shown in FIG. 13;

FIG. 15 is a sectional view obtained by cutting the lateral bipolar transistor according to the third embodiment of the present invention along Y1-Y1′ plane shown in FIG. 13;

FIG. 16 is a sectional views obtained by cutting the lateral bipolar transistor according to the third embodiment of the present invention along Y2-Y2′ plane shown in FIG. 13;

FIG. 17 is a diagram for describing the construction of a lateral bipolar transistor according to the fourth embodiment of the present invention

FIG. 18 is a diagram for describing the construction of a lateral bipolar transistor according to a fifth embodiment of the present invention;

FIG. 19 is a plan view of a lateral bipolar transistor which is a modification of the fifth embodiment of the present invention;

FIG. 20 is a diagram for describing the construction of a lateral bipolar transistor according to a sixth embodiment of the present invention;

FIGS. 21 through 24 are diagrams for describing a fabricating method of the lateral bipolar transistor of the first embodiment of the present invention;

FIG. 25 is a diagram for describing the construction of a lateral bipolar transistor according to a seventh embodiment of the present invention;

FIGS. 26 and 27 are diagrams for describing a fabricating method of the lateral bipolar transistor of the seventh embodiment of the present invention.

Claims

1. A lateral bipolar transistor formed over a substrate of an SOI structure having a silicon layer provided over an embedded insulating film layer, comprising: emitter diffusion regions formed in the substrate;a base drawing diffusion region formed at a position away from each of the emitter diffusion regions;isolation insulating films that reach the embedded insulating film layer and are formed between the emitter diffusion regions and the base drawing diffusion region;a base diffusion region including, on both sides of the isolation insulating films, two end areas respectively brought into contact with the side faces of the isolation insulating films while ensuring electrical connections to the base drawing diffusion region, and central areas formed integrally with the two end areas so as to cover the peripheries of the emitter diffusion regions; anda collector diffusion region at least formed around the central areas of the base diffusion region.

2. The lateral bipolar transistor according to claim 1, wherein the emitter diffusion regions and the isolation insulting films are respectively provided on both sides of the base drawing diffusion region, wherein the base diffusion region is formed in a ring form so as to surround the peripheries of the base drawing diffusion region, the two isolation insulating films disposed on both sides of the base drawing diffusion region and the two emitter diffusion regions disposed outside the isolation insulating films, andwherein the collector diffusion region is formed in ring form so as to cover the periphery of the base diffusion region.

3. The lateral bipolar transistor according to claim 2, further including a base wiring provided with respect to the base drawing diffusion region; an emitter wiring provided in common with all of the emitter diffusion regions; anda collector wiring provided with respect to the collector diffusion region.

4. The lateral bipolar transistor according to claim 1, wherein the central areas of the base diffusion regions respectively have three sides connected to one another so as to surround the emitter diffusion regions, and wherein connecting portions of the three sides are respectively brought into corner-cut shapes.

5. A lateral bipolar transistor formed over a substrate of an SOI structure having a silicon layer provided over an embedded insulating film layer, comprising: an emitter diffusion region formed in the substrate;two base diffusion regions formed so as to interpose the emitter diffusion region therebetween;two collector diffusion regions formed so as to interpose the emitter diffusion region and the two base diffusion regions therebetween;at least two base drawing diffusion regions formed at positions away from the emitter diffusion region in a state of being respectively electrically connected to the two base diffusion regions; andan isolation insulating film formed so as to be adjacent to the portion of an emitter diffusion region which is not in contact with the base diffusion regions, and reach the embedded insulating film layer.

6. A lateral bipolar transistor wherein the lateral bipolar transistor according to claim 5 is disposed in parallel in plural form in such a manner that the collector diffusion regions overlap each other.

7. A lateral bipolar transistor wherein the lateral bipolar transistor according to claim 5 is disposed in parallel in plural form in such a manner that the base drawing diffusion regions overlap each other.

8. The lateral bipolar transistor according to claim 6, further comprising: an emitter wiring provided in common with all of the emitter diffusion regions arranged in plural form,a collector wiring provided in common with all of the collector diffusion regions arranged in plural form, anda base wiring provided in common with all of the base drawing diffusion regions arranged in plural form.

9. The lateral bipolar transistor according to claim 1, wherein each of the base diffusion regions is prepared in the form of a first conduction type, wherein a MOS transistor which includes a gate insulating film and a gate conductive layer prepared in the form of a second conduction type different from the first conduction type and is constructed so as to form a channel of the second conduction type, is formed over the substrate, andwherein the lateral bipolar transistor further includes an insulating film which covers the surfaces of the base diffusion regions, and conductive layers formed over the insulating film in a state in which the characteristic of the second conduction type is suppressed as compared with the gate conductive layer.

10. The lateral bipolar transistor according to claim 9, wherein the gate conductive layers over the base diffusion regions are intrinsic from the viewpoint of a conduction type.

11. The lateral bipolar transistor according to claim 9, wherein the conductive layers over the base diffusion regions are prepared in the first conduction type the same as the base diffusion regions.