| 摘要 |
1,244,508. Semi-conductor devices. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. 11 Dec., 1968 [14 Dec., 1967], No. 58827/68. Heading H1K. A Zener diode having an abrupt junction is manufactured by out-diffusing impurities from the surface of a first diffused region 9 of the diode so as to reverse the concentration gradient thereof adjacent the surface, then diffusing a second region 16 of the opposite conductivity type into the out-diffused part of the region 9 to a depth at most equal to that over which the concentration gradient of the region 9 has been reversed. In the embodiment shown, an integrated circuit includes such a diode and an NPN transistor formed in an N-type epitaxial layer 5 on a P-type Si substrate 1. The transistor collector region includes a buried As-doped N + layer 11 which, together with the lower part of a B-doped P+ isolation zone 10, is formed by redistribution of impurities from prediffused regions on the surface of the substrate 1. Outdiffusion of B from the Zener diode region 9 occurs into a dry oxygen atmosphere during diffusion of the B-doped and P-doped base and emitter regions 13, 15 respectively of the transistor. Finally, the P-doped N+ region 16 is diffused. Part of the surface of the region 9 may be covered to prevent out-diffusion therefrom so as to provide a highly-doped contact zone. Other embodiments include a similar Zener diode integrated with a PNP transistor in an N-type epitaxial layer (22), Fig. 4 (not shown), on an N-type substrate (21), and a structure which is, in general, complementary to that illustrated in Fig. 3j (Fig. 5, not shown). Ge or III-V compounds are alternative semiconductor materials, while field-effect transistors, resistors and capacitors may also be formed in integrated circuits with the Zener diode of the invention.
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