Semiconductor device manufacturing: process – Making field effect device having pair of active regions... – Having insulated gate
Reexamination Certificate
2000-11-08
2002-10-08
Pham, Long (Department: 2823)
Semiconductor device manufacturing: process
Making field effect device having pair of active regions...
Having insulated gate
C438S238000, C438S239000, C438S381000
Reexamination Certificate
active
06461910
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to a method of manufacturing a capacitor in a semiconductor device. More particularly, it relates to a method of manufacturing a capacitor in a semiconductor device capable of improving the leak current characteristic while preventing degradation of a dielectric characteristic of a Ta
2
O
5
capacitor.
2. Description of the Prior Art
Generally, the Ta
2
O
5
capacitor is manufactured in a MIS (Metal-Insulator-Silicon) structure in which a TiN film/polysilicon film structure is stacked as an upper electrode. The reason why the stacked TiN film/polysilicon film is used, is that it can improve the leak current characteristic of the TiN film since it has the value of a higher work function compared with the polysilicon film.
However, there are the following problems when using the TiN film as the upper electrode. That is, the process of forming a CVD TiN film using a mixed gas of TiCl
4
+NH
3
will increase the leak current in the Ta
2
O
5
dielectric film due to a halogen gas. Also, there will happen an interface reaction between the Ta
2
O
5
dielectric film and the TiN film at the temperature of about 500° C., thus causing oxygen within the Ta
2
O
5
dielectric film to flow into the TiN film. Thus, oxygen vacancy will be created within the Ta
2
O
5
dielectric film, resulting in increase of the leak current. The reaction between the Ta
2
O
5
dielectric film and the TiN film can be expressed into the following chemical equation. The TiO
2
film formed by this chemical reaction will degrade the capacitor characteristic of the TiO
2
film.
5TiN+2Ta
2
O
5
→TiO
2
+4TaN+1/2N
2
[Equation 1]
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a method of manufacturing a capacitor in a semiconductor device by which TaN is used as an upper electrode, which can improve the leak current characteristic of a Ta
2
O
5
capacitor due to the high work function of a TaN while preventing degradation of the dielectric characteristic of the Ta
2
O
5
capacitor, in order to prevent degradation of the dielectric characteristic due to the interface reaction between a Ta
2
O
5
dielectric film and a TiN upper electrode in the Ta
2
O
5
capacitor.
In order to accomplish the above object, a method of manufacturing a capacitor in a semiconductor device according to the present invention is characterized in that it comprises the steps of forming a lower electrode on a semiconductor substrate in which various components for forming a semiconductor device are formed, forming a Ta
2
O
5
dielectric film on said lower electrode; and forming an upper electrode made of a TaN film on said Ta
2
O
5
dielectric film.
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Jeon Kwang Seok
Park Dong Su
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Hyundai Electronics Industries Co,. Ltd.
Pham Long
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