A NEW CONCEPT OF P(-)(N(-)) P(-)(N(-)) THIN-FILM EPITAXIAL SILICON-WAFERS FOR MOS ULSIS THAT ENSURES EXCELLENT GATE OXIDE INTEGRITY/

A new concept of epitaxial silicon (Si) wafers (NC epi.) in which p(-) (n(-)) thin-film layers are grown on p(-)(n(-)) Czochralski (CZ)-Si su bstrates (substrate resistivity: approximately 10 Ohm cm) is proposed for metal oxide semiconductor (MOS) ultra large-scale integrated circu its (ULSI's) as a starting material. A thickness of 0.3-1 mu m for the epitaxial layer (p(-)/p(-) structure) is shown to be sufficient for i mproving the gate oxide integrity for MOS-ULSI's. The epitaxial layer grown on Si substrate greatly reduces weak spots in the gate oxide lay er by covering microdefects in the CZ-Si represented by crystal origin ated particle (COP). The p(-)/p(-) thin-film epitaxial structure resul ts in very controlled resistivity for the electrically active region i n the device, which in turn results in a lower growth cost and higher feasibility for use in current ULSI's. The features of NC epi. in comb ination with proximity gettering is presented. An application of NC ep i. in shallow-trench isolation processes discussed considering retrogr ade-type well-tub. The amenability of epitaxial wafers to wafer enlarg ement lover 300 mm) is discussed to eliminate bad effects of COP.