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Abstract

A novel process for forming a robust, sub-100 Å oxide is disclosed. Native oxide growth is tightly controlled by flowing pure nitrogen during wafer push and nitrogen with a small amount of oxygen during temperature ramp and stabilization. First, a dry oxidation is performed in oxygen and 13% trichloroethane. Next, a wet oxidation in pyrogenic steam is performed to produce a total oxide thickness of approximately 80 Å. The oxide layer formed is ideally suited for use as a high integrity gate oxide below 100 Å. The invention is particularly useful in devices with advanced, recessed field isolation where sharp silicon edges are difficult to oxidize. For an oxide layer of more than 100 Å, a composite oxide stack is used which comprises 40-90 Å of pad oxide formed using the above novel process, and 60-200 Å of deposited oxide.

Other References

• Wolf et al., “Silicon Processing for the VLSI Era, vol. 1: Process Technology”, pp. 201-207, Lattice Press, 1986.
• Ghandhi, “VLSI Fabrication Principles”, 1983, pp. 385-388, John Wiley and Sons, 1983.*
• C. Wei, Y. Nissan-Cohen, and H. Woodbury; “Evaluation of 850° C. Wet Oxideee As The Gate Dielectric In A 0.8 μm CMOS Process”; IEEE Transactions On Electron Devices; vol. 38, No. 11 (Nov. 1991); pp. 2433-2441.*
• R.G. Cosway and C.E. Wu; Comparison Of Thin Thermal SiO₂ Grown Using HCl and 1,1,1 Trichloroethane (TCA); Journal Of The Electrochemical Society; Solid-State Science and Technology; vol. 132, No. 1, (Jan. 1985); pp. 151-154.*
• Y.C. Cheng and B.Y. Liu; “Oxidation Characteristics And Electrical Properties Of Low Pressure Dual TCE Oxides”; Journal Of The Electrochemical Society: Solid-State Science and Technology; vol. 131, No. 2, (Feb. 1984); pp. 354-358.*
• B.Y. Liu and Y.C. Cheng; “Growth and Characterization Of Thin Gate Oxides By Dual TCE Process”; Journal Of The Electrochemical Society-Accelerated Brief Communication; vol. 131, No. 3, (Mar. 1984); pp. 683-686.*
• M.B. Das, J. Stach, and R.E. Tressler; “A Comparison Of HCl-And Trichloroethylene-Grown Oxides On Silicon”; Journal Of The Electrochemical Society: Solid-State Science and Technology; vol. 131, No. 2, (Feb. 1984); pp. 389-392.*
• F. Bryant and F. Liou; “Thin Gate Oxides Grown in Argon Diluted Oxygen With Steam and HCL Treatment”; Proceedings Of The Symposium On Silicon Nitride and Silicon Dioxide Thin Insulating Films; vol. 89-7, 1989; pp. 220-228.*
• S. Wolf; “Silicon Processing For The VLSI Era”; vol. 2, Chapter 2, 1990.*
• S. Wolf and R.N. Tauber; “Silicon Processing For The VLSI Era”; vol. 1, Chapter 7, 1986; pp. 215-216.*
• Deal, B.; “The Oxidation . . . and Steam”; J. Electochem Society; vol. 110, No. 6, Jun. 1968; pp. 527-533.*
• Gdula, R.; “Composite Dielectric Layer”; IBM Tech. Disc. Bull., vol. 14, No. 9, Feb. 1972; p. 2609.*
• Montillo, F.; “High Temperature Annealing . . . Surfaces”; J. Electrochem. Soc., vol. 188, No. 9, Sep. 1971; pp. 1463-1468.*
• Kanigaki, Y.; “Thermal Oxidation . . . by Nitrogen”; Appl. Phys.; vol. 48, No. 7, Jul. 1977; pp. 2891-2896.*
• Wolf et al., “Silicon Processing for the VLSI Era vol. 1: Process Technology”, Lattice Press, pp. 215-216, 1986.*