GB1366967A - Bidirectional thyristor with ignition properties - Google Patents

Abstract

1366967 Semi-conductor devices TRANSISTOR AG 21 Dec 1972 [29 Dec 1971] 59270/72 Heading H1K At the upper surface 2 (Fig. 1a) of a bidirectional thyristor the N-type emitter region 9, together with an auxiliary strip 9<SP>1</SP> thereof, completely encloses an area 18 of the adjacent P-type region 7 containing a further isolated N- type region 11. The main electrode 13 contacts both the emitter region 9/9<SP>1</SP> and the P-type region 7 while the control electrode 14 contacts both the further N-type region 11 and the area 18 of the P type region 7. At the lower surface 3 (Fig. 1c) the N-type emitter region 12 includes a portion 12<SP>1</SP> whose outer periphery is of the same length and shape as the outer periphery of the auxiliary emitter strip 9<SP>1</SP> on the upper surface. The main electrode 15 contacts both the emitter region 12/12<SP>1</SP> and the adjacent P-type region 6. The various regions are arranged, as shown, symmetrically across a central plane S of the device. Preferably the parts of the P-type regions which are contacted are of relatively high conductivity. In the configuration shown the isolated N-type region 11 on the upper surface 2 is semicircular, there being an associated complementary semicircular P<SP>+</SP>-type zone 10. In a modification the region 11 is of half-ring shape, the P<SP>+</SP> zone then being shaped once more to complete a central circular area of the surface 2. Rectangular modifications of both these alternatives are also described.