Method of reducing carbon contamination of a thin dielectric film by using gaseous organic precursors, inert gas, and ozone to react with carbon contaminants
First Claim
1. A process for forming a thin film of dielectric on a semiconductor substrate, said film having reduced carbon contamination, comprising heating the substrate under an inert atmosphere in a suitable reaction chamber to a temperature such that a selected gaseous organic precursor for said dielectric will react to form a bonded reactant on the surface, and carrying out multiple deposition cycles at said temperature to form said thin dielectric film, each deposition cycle comprising:
- a) introducing the gaseous organic precursor into the reaction chamber so that it reacts to form said bonded reactant on the surface;
b) purging the reaction chamber with an inert gas;
c) introducing a second gaseous reactant into the chamber which reacts with said bonded reactant to form said dielectric film; and
d) purging the reaction chamber with the inert gas,wherein no less frequently than every third cycle, introducing ozone into the reaction chamber following step d) to react with carbon contaminants in the film thereby forming gaseous products and purging the reaction chamber with said inert gas to remove such products prior to initiating the next cycle.
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Abstract
A process is provided for the formation of a thin film of gate dielectric or similar material on a silicon semiconductor substrate from an organic precursor by atomic layer epitaxy, wherein the organic precursor is introduced to react with the treated surface to form a bonded monolayer of reactive species. A second reactant is introduced to react with the surface to form the desired dielectric. After each step in the cycle, the reaction chamber is purged with an inert gas to prevent reactions except on the surface. The cycle is repeated tens to hundreds of times to achieve a desired final film thickness. No less frequently than every third cycle, the film undergoes a discrete treatment step wherein ozone is introduced into the chamber to oxidize carbon contaminants therein to form volatile products which are removed from the reaction chamber by purging with the inert gas. In a preferred embodiment where the substrate is silicon or polysilicon, a sub-monolayer of a protection material is formed by boding to silicon sites on the surface before the deposition of dielectric is begun. A preferred dielectric is gate aluminum oxide that is deposited using trimethyl aluminum as a precursor.
336 Citations
25 Claims
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1. A process for forming a thin film of dielectric on a semiconductor substrate, said film having reduced carbon contamination, comprising heating the substrate under an inert atmosphere in a suitable reaction chamber to a temperature such that a selected gaseous organic precursor for said dielectric will react to form a bonded reactant on the surface, and carrying out multiple deposition cycles at said temperature to form said thin dielectric film, each deposition cycle comprising:
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a) introducing the gaseous organic precursor into the reaction chamber so that it reacts to form said bonded reactant on the surface; b) purging the reaction chamber with an inert gas; c) introducing a second gaseous reactant into the chamber which reacts with said bonded reactant to form said dielectric film; and d) purging the reaction chamber with the inert gas, wherein no less frequently than every third cycle, introducing ozone into the reaction chamber following step d) to react with carbon contaminants in the film thereby forming gaseous products and purging the reaction chamber with said inert gas to remove such products prior to initiating the next cycle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 23)
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19. A process for forming a thin film of aluminum oxide gate dielectric on a semiconductor substrate, said film having reduced carbon contamination, comprising heating the substrate under an inert atmosphere in a suitable reaction chamber to a temperature such that a trimethyl aluminum will react to form a bonded reactant on the surface thereof, treating the surface of the substrate with water vapor to form hydroxyl groups thereon and carrying out multiple deposition cycles at said temperature to form said thin gate dielectric film, each deposition cycle comprising:
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a) introducing trimethyl aluminum into the reaction chamber so that it reacts to form said bonded reactant on the surface; b) purging the reaction chamber with an inert gas; c) introducing water vapor into the chamber which reacts with said bonded reactant to form said aluminum oxide gate dielectric film; and d) purging the reaction chamber with the inert gas, wherein no less frequently than every third cycle, introducing ozone into the reaction chamber following step d) to react with carbon contaminants in the film thereby forming gaseous products and purging the reaction chamber with said inert gas to remove such products prior to initiating the next cycle. - View Dependent Claims (20, 21, 22, 24, 25)
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Specification