Chemistry: molecular biology and microbiology – Animal cell – per se ; composition thereof; process of... – Primate cell – per se
Reexamination Certificate
1996-06-27
2001-02-20
Mulpuri, Savitri (Department: 2812)
Chemistry: molecular biology and microbiology
Animal cell, per se ; composition thereof; process of...
Primate cell, per se
C438S532000, C438S597000, C438S369000
Reexamination Certificate
active
06190911
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to semiconductor devices and fabrication methods thereof, and more particularly to semiconductor devices wherein the connection of the semiconductor device with the wiring is improved and to fabrication methods thereof.
2. Related Background Art
In recent years, as the higher integration of semiconductor devices has been made, the area of each part within a chip has been reduced, wherein it is an important problem to reduce the area of the wiring part because it occupies a large percentage of the chip area. Concerning the lead-out part to the wiring of a semi-conductor device or a so-called contact part, while it was conventionally practiced that after an ohmic contact material composed of group IV polycrystalline semi-conductor material was laid down at a position directly above the element, the electrode of a metal or metal silicide containing a low-melting metal such as Al and the group IV polycrystalline semiconductor material were joined off the position directly above the element. It is contemplated that a metal or metal silicide is also joined directly above the element at the same time.
On the other hand, a polycrystalline semiconductor material (e.g., group N) is undesirable to use as the lead-out wiring, because as the operation frequency of the element increases, the movement of carriers for carrying electric current can not follow it, whereby such a constitution is now being adopted that the electrode of metal or metal silicide is contacted directly above the element from the viewpoint of high speed operation.
However, a low-melting metal in the metal or metal silicide for use as low resistive wiring material greatly diffuses into polycrystalline semiconductor material, and when a metal or metal silicide contact is made directly above the element, the low-melting metal will diffuse into the element portion, bringing the above degradation of element characteristics in some cases. Accordingly, to suppress the diffusion of low-melting metal, a barrier metal may be disposed between the metal or metal silicide and polycrystalline semiconductor material. With this constitution, the diffusion of a low-melting metal is surely suppressed, and there is no degradation of element characteristics, but because of a step of depositing and patterning the barrier metal interposed, the process is more complex, with increased cost.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a semiconductor device and a fabrication method thereof, wherein with a structure and a method not involving any complex process and increased cost at the contact part of the semiconductor device, the diffusion of a low-melting metal can be suppressed without degradation of the element characteristics.
Also, it is another object of the present invention to provide a semiconductor device without degradation of the characteristics by preventing the diffusion of wiring metal to the element area of the semiconductor device, while simplifying the process by disposing wiring metal directly above the element area to eliminate unnecessary wiring.
Also, it is a further object of the present invention to provide a method for fabricating a semi-conductor device having a wiring part connected via an opening portion formed in an insulating film on a semi-conductor region to said semiconductor region, including the steps of:
depositing a polycrystalline semiconductor layer over said opening portion on said semiconductor region,
ion injecting impurities having a large range into said polycrystalline semiconductor layer,
ion injecting impurities having a small range into said polycrystalline semiconductor layer,
conducting heat treatment after ion injection of said impurities, and
depositing a metal or metal silicide containing a low-melting metal on said polycrystalline semi-conductor layer after said heat treatment.
Also, it is another object of the present invention to provide a semiconductor device comprised of a semiconductor region, an insulating film applied on said semiconductor region, and a wiring part connected via an opening portion formed in said insulating film to said semiconductor region,
wherein said wiring part has disposed a metal or metal silicide at least containing a low-melting metal on an upper layer, and a polycrystalline semiconductor material containing p-type impurities on a lower layer, and at least one of the elements of germanium, tin, phosphorus, arsenic, antimony, gallium, and indium is injected into a group IV polycrystalline semiconductor material layer.
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Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Mulpuri Savitri
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