Method for fabricating tantalum semiconductor contacts
AssigneeInternational Business Machines Corporation
InventorsHormazdyar M. Dalal, Majid Ghafghaichi, Lucian A. Kasprzak, Hans Wimpfheimer
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Abstract
A silicon semiconductor device having contacts which include tantalum. The tantalum is useful in particular for fabricating Schottky barrier diodes having a low barrier height. The method includes: precleaning the silicon substrate prior to depositing the tantalum; depositing the tantalum at low pressure and low substrate temperature to avoid oxidation of the tantalum; and sintering the contact to reduce any interfacial charges and films remaining between the silicon and tantalum. When a metal which reacts with silicon during processing, such as aluminum, is used as interconnection metallurgy, a layer of chrome must be deposited between the tantalum and aluminum.
Claims20
A method for fabricating a tantalum contact on a silicon semiconductor substrate which exhibits N- type conductivity, whereby said contact is a low-barrier-height Schottky barrier diode comprising:
- cleaning the surface of at least a portion of said substrate with a dilute HF etchant solution under conditions in which there is no substantial amount of light shorter than a wavelength of 5000 A so as to prevent the formation of amorphous silicon;
- depositing tantalum atop said portion of said substrate in a vacuum chamber at a low pressure and substrate temperature so as to avoid oxidation of said tantalum;
- and
- sintering said substrate at a sufficient temperature and time to remove interfacial charges and films from between said substrate and said tantalum.
A method for fabricating a tantalum contact on a silicon semiconductor substrate comprising:
- preparing the surface of at least a portion of said substrate so as to prevent the formation of amorphous silicon by cleaning said surface in a dilute HF etchant solution under conditions in which there is no substantial amount of light shorter than the wavelength of 5000 A;
- depositing tantalum atop said portion of said substrate in a vacuum chamber at a low pressure and substrate temperature so as to avoid oxidation of said tantalum;
- and
- sintering said substrate at a sufficient temperature and time to remove interfacial charges and films from between said substrate and said tantalum.
A method for fabricating a tantalum contact on a silicon semiconductor substrate comprising:
- cleaning the surface of at least a portion of said substrate so as to prevent the formation of amorphous silicon;
- depositing tantalum atop said portion of said substrate in a vacuum chamber at a low pressure and substrate temperature so as to avoid oxidation of said tantalum;
- sintering said substrate at a sufficient temperature and time to remove interfacial charges and films from between said substrate and said tantalum and
- depositing chrome atop said tantalum.
Dependencies are inferred from the claim text.