| 摘要 |
1,140,643. Transistors. SIEMENS A.G. 11 Sept., 1967 [12 Sept., 1966], No. 41355/67. Heading H1K. A transistor designed particularly for use in grounded emitter configuration has a surface coating of insulant covering the exposed edges of the emitter and collector junctions and the surface of the base region between them, and the emitter contact extends over this layer from the emitter across the base to terminate above the collector. This extended contact should completely overlie the space charge zone which in use arises adjacent the collector junction, and for this reason it includes a portion in the form of a closed loop following the periphery of the collector junction. The invention, though particularly applicable to planar transistors, is also applicable to other structures, e.g. mesas. It can also be applied to any transistors in an integrated circuit. Fig. 3 shows a plan view of one embodiment in which: lines 9 and 10 indicate the peripheries of the emitter and collector junctions; shaded area 5 is the base contact; and the larger shaded area is the emitter contact which includes a portion 6 breaking through the surface insulant to contact the emitter region and a surrounding portion 7 which overlies the insulant. In Fig. 4 the emitter region 3 is annular and its contact 6 concentrically surrounds the base contact 5. Figs. 2 and 5 (not shown) depict further alternative structures: Fig. 5 is a plan view of a structure similar to that of Fig. 3 except that the generally rectangular shapes are replaced by circular ones; and Fig. 2 is a sectional view of a similar structure to that of Figs. 3 and 5. In any of the structures described the collector contact 8 may be on the opposite side of the wafer to the base and emitter contacts, or on the wafer edge as in Fig. 4, or on the same face as the base and emitter contacts-in which case it may be in the form of a ring contact surrounding the other two contacts. |
