| 摘要 |
1372086 Semi-conductor devices PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 18 Nov 1971 [21 Nov 1970] 53609/71 Heading H1K The channel region of an IGFET is formed in a portion of a region 6 from which out-diffusion of characteristic impurity has been effected into an atmosphere of reduced pressure so as to provide a net impurity distribution in the region 6 having a zone 10 of maximum concentration at a position beneath the semi-conductor surface. The source and drain regions 8, 9 (of the opposite conductivity type) may be formed (as shown) entirely within the outdiffused portion or may be formed to be partially within it. The structure of Fig. 2, is formed by the growth on a P-type silicon substrate of an N- type epitaxial layer 3 into which boron is diffused to provide region 6 and isolation walls 18. Boron is out-diffused from region 6 through the original mask for in-diffusion (though in variants the entire surface of region 6 may be exposed) into an evacuated enclosure which may contain a source of undoped silicon to inhibit loss of silicon from the surface. A complementary IGFET and a bi-polar transistor are provided in respective isolated islands of the epitaxial layer. Figs. 10, 13, and 14 (not shown) depict structures formed in substrates of one conductivity type (and not having an epitaxial layer formed thereon) and having respectively an IGFET formed in the outdiffused portion of a surface region of a second conductivity type and a complementary IGFET formed in an adjacent part of the bulk; three IGFETs of the same type each formed in respective out-diffused portions of a single surface region of opposite conductivity type to the substrate; and a single IGFET formed in the out-diffused portion of a surface region and a bi-polar transistor formed in the bulk which it utilizes as its collector region. In the structure of Fig. 10, the IGFET 8, 12, 9 in the outdiffused portion 11 is complemented by an IGFET using the surface region 11, 6 as source and having a gate 41 and drain 40. It is not necessary for the region to be out-diffused to be provided by in-diffusion; the initial region may be formed by ion-implantation.. Reference has been directed by the Comptroller to Specification 1,128,553.
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