Active solid-state devices (e.g. – transistors – solid-state diode – Non-single crystal – or recrystallized – semiconductor... – Field effect device in non-single crystal – or...
Reexamination Certificate
2001-08-16
2003-06-10
Flynn, Nathan J. (Department: 2826)
Active solid-state devices (e.g., transistors, solid-state diode
Non-single crystal, or recrystallized, semiconductor...
Field effect device in non-single crystal, or...
C257S301000, C257S532000, C257S534000, C438S152000
Reexamination Certificate
active
06576928
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a semiconductor device containing a capacitor wherein a metal oxide of tantalum pentoxide, and the like, is used as dielectrics and a method for manufacturing thereof.
In semiconductor devices having LSI such as dynamic random access memory (DRAM), etc., the capacitor area is reduced with higher integration. Thus, there is studied application of metal oxide dielectrics such as tantalum pentoxide (Ta
2
O
5
) having high permittivity of several tens in place of the silicon oxide which has been used as capacitor dielectric film. Further, in gigabit generation semiconductor devices wherein the minimum processing size is 0.15 &mgr;m or less, it is necessary to form a dielectric film by using a CVD (chemical vapor deposition) method on a surface of deep hole or concave in order to enhance capacitance, even if metal oxide dielectrics having a higher permittivity are used.
High dielectric Ta
2
O
5
's applied so far can be summarized as follows.
1) In a capacitor using MIS (metal-insulator-semiconductor)-Ta
2
O
5
film, the permittivity increases to 40 at most depending on conditions of CVD method and heat treatment. It is estimated that the crystal phase transfers to a &dgr; phase, but this is not identified precisely.
2) MIM (metal-insulator-metal)-Ta
2
O
5
film has a large permittivity of from 40 (formed by CVD) to 80 (formed by sputtering) depending on film preparation and heat treatment conditions. It is estimated that the crystal phase transfers to a &dgr; phase, but this is not identified.
3) Ta
2
O
5
film obtained by adding TiO
2
or Al
2
O
3
and heat-treated at about 1400° C. has a high permittivity of 126 at most. The crystal phase is monoclinic H′ phase or a mixture, respectively.
However, the high dielectric Ta
2
O
5
's mentioned above have problems mentioned below, respectively.
First, in the case of MIS-Ta
2
O
5
formed on a silicon nitride film, the permittivity is higher than a typical value of 25 of the L phase, but retains at about 40. Next, in the case of Ta2O5 formed on Pt by a sputtering method, the permittivity is as high as 75 or more, but the preparation temperature is as high as 550° C. Considering application to devices, for example, in order to form a Ta
2
O
5
film uniformly on inner walls of a deep hole by using a CVD method, it is required a technology to form the film at a temperature of 500° C. or less. In the case of forming high dielectric Ta
2
O
5
on Ru, a heat treating temperature of 750° C. or higher is necessary. Considering application to device processes, technology of reducing to the temperature of 700° C. or less is required. In addition, properties of these MIM and MIS capacitors are largely dependent on preparation conditions and heat treating conditions, and lack in reproducibility. As to the addition of TiO
2
and Al
2
O
3
, since high temperature heat treatment of 1400° C. is necessary, application to the device processes is impossible.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention is to provide a semiconductor device containing MIS or MIM capacitor having hexagonal phase and permittivity of 50 or more. More concretely, by using a dielectric film made of a solid solution of tantalum pentoxide and niobium pentoxide with a film thickness of 10 nm or less, the above object is attained.
Another object of the present invention is to provide a method of manufacturing such a semiconductor device.
REFERENCES:
patent: 5520992 (1996-05-01), Douglas et al.
patent: 6222722 (2001-04-01), Fukuzumi et al.
patent: 9-2869 (1997-01-01), None
patent: 10-93051 (1998-04-01), None
patent: 10-182221 (1998-07-01), None
patent: 11-16624 (1999-01-01), None
IDS p. 2, Reference AS, Khitrova et al., Sov. Phys. Crystallogr. vol. 24, 1979, pp. 537-539.*
1999 Symposium on VLSI Technology, Digest of Technical Papers, pp. 99-100.
Journal of Research of the National Bureau of Standards, vol. 72A, 1968, pp. 175-186.
Acta Cryst. vol. 14, 1961, pp. 1278-1281.
Japanese Journal of Applied Physics, vol. 6, 1967, pp. 21-34.
Sov. Phys. Cyrstallogr. vol. 24, 1979, pp. 537-539.
Sov. Phys. Crystallogr. vol. 25, 1980, pp. 669-672.
Extended Abstracts of the 1991 International Conference on Solid State Devices and Materials, pp. 198-200.
Extended Abstracts of the 1997 International Conference on Solid State Devices and Materials, pp. 36-37.
Hamada Tomoyuki
Hiratani Masahiko
Kimura Shin'ichiro
Flynn Nathan J.
Hitachi , Ltd.
Mattingly Stanger & Malur, P.C.
Wilson Scott
LandOfFree
Semiconductor device capacitor with high permittivity... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Semiconductor device capacitor with high permittivity..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Semiconductor device capacitor with high permittivity... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3148217