Synthesis and characterization of high quality ultrathin gate oxides for VLSI/ULSI circuits

A major hurdle in VLSI/ULSI technology has been the inability to grow ultrathin oxides with low defect and interface trap densities and to generate a planar stress-free silicon/silicon-dioxide (Si/SiO/sub 2/) interface. The authors describe the fabrication of thin multilayered stacked SiO/sub 2/ structure with such qualities. A huge improvement in the quality of these stacked oxides has been achieved through a novel synthesis of a three-step process which involves growing, depositing, and growing SiO/sub 2/ layers on silicon substrates by thermal oxidation, chemical vapor deposition, and densification/oxidation, respectively. These oxides have the ideal combination of low defect and interface trap densities, and the Si/SiO/sub 2/ interface generated during the synthesis is structurally superior.<>