| 摘要 |
1510276 Semiconductor devices SIEMENS AG 25 June 1976 [2 July 1975] 26455/76 Heading H1K In a process, suitable for producing a bipolar integrated circuit on a doped semiconductor substrate, a doped zone or zones of a bipolar transistor and an insulating frame for the transistor are formed in etched troughs in the substrate surface formed through windows in a surface insulating layer. The remaining required doped transistor zones are formed by introducing dopant through the flank surface of the troughs which have been exposed by preferential ion beam etching through a mask at normal incidence through a further insulating layer applied to the substrate surface within the troughs. In the embodiment shown, a p-type silicon substrate 1, covered with a silicon oxide layer 22, has troughs 71 in which p<+>-type zones 72 are produced by ion implantation to form an isolation frame. The base zone of the bipolar transistor is formed by ion implantation of p<+>-type zone 92 through a photo-lacquer or Al masking layer (not shown), above a window 6 over the trough 611, and into a previously formed ion implanted n-type zone 91. A further insulating layer 10 is formed in the troughs by thermally oxidizing the surface, following the removal of the mask. During the thermal oxidation, further diffusion of zones 91 and 72 occurs, to yield zones 911, 721, and also zone 92 extends to yield zone 921, Fig. 6. A masking layer 12, of photolacquer or Al, is applied before bombardment by a vertical ion beam 19, Fig. 7. This bombardment removes the oxide at the oblique flanks 14 twice as rapidly as at the horizontal oxide surface within the troughs, to yield the reduced oxide layer 101 shown in Fig. 7. In a further step, Fig. 8, the masking layer 12 is removed, and replaced by another masking layer, of photo-lacquer or Al, structured to allow ion beam n<++>-type doping of the exposed trough flanks 14, to yield emitter zone 16 and collector zone 17 of the bipolar transistor having a base zone 921. The process of the invention can be applied to the production of p-n diodes, Schottky diodes, resistors, or multi-emitters.
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