Silicon-rich nickel-silicide ohmic contacts for SiC semiconductor devices
First Claim
1. A method of producing an ohmic contact to silicon carbide comprising:
- providing a film of nickel and silicon on a silicon carbide surface in respective proportions so that the atomic fraction of silicon in the film is greater than the atomic fraction of nickel;
heating the film of nickel and silicon at a temperature between about 200 and 500°
C. to form a nickel-silicon compound; and
annealing the nickel-silicon compound to a temperature higher than the heating temperature for the film, and within a region of a phase diagram at which free carbon does not exist.
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Abstract
A method of producing an ohmic contact and a resulting ohmic contact structure are disclosed. The method includes the steps of forming a deposited film of nickel and silicon on a silicon carbide surface at a temperature below which either element will react with silicon carbide and in respective proportions so that the atomic fraction of silicon in the deposited film is greater than the atomic fraction of nickel, and heating the deposited film of nickel and silicon to a temperature at which nickel-silicon compounds will form with an atomic fraction of silicon greater than the atomic fraction of nickel but below the temperature at which either element will react with silicon carbide. The method can further include the step of annealing the nickel-silicon compound to a temperature higher than the heating temperature for the deposited film, and within a region of the phase diagram at which free carbon does not exist.
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Citations
19 Claims
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1. A method of producing an ohmic contact to silicon carbide comprising:
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providing a film of nickel and silicon on a silicon carbide surface in respective proportions so that the atomic fraction of silicon in the film is greater than the atomic fraction of nickel; heating the film of nickel and silicon at a temperature between about 200 and 500°
C. to form a nickel-silicon compound; andannealing the nickel-silicon compound to a temperature higher than the heating temperature for the film, and within a region of a phase diagram at which free carbon does not exist. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of producing an ohmic contact to silicon carbide comprising:
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depositing a layer of nickel and a layer of silicon in respective proportional thicknesses on a silicon carbide surface so that the atomic fraction of silicon in the deposited layers is greater than the atomic fraction of nickel in the deposited layers; depositing the layers of nickel and silicon at a temperature below which either element will react with silicon carbide; and thereafter heating the deposited layers of nickel and silicon to a temperature at which nickel-silicon compounds will form with an atomic fraction of silicon greater than the atomic fraction of nickel but below the temperature at which either element will react with silicon carbide. - View Dependent Claims (15, 16, 17)
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18. A method of producing an ohmic contact to silicon carbide comprising:
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providing a film of nickel and silicon on a silicon carbide surface in respective proportions so that the atomic fraction of silicon in the film is greater than the atomic fraction of nickel; heating the film at a temperature below 500°
C.; andthereafter annealing the film at a temperature of between 500 and 900°
C. - View Dependent Claims (19)
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Specification