JPS63318009A - Dielectric substance film - Google Patents

Abstract

PURPOSE:To provide high quality Ta2O5 film with less leak current by allowing the film to contain one or more elements such as Ba, Fe, Pb, Sc, Sr, Zn, La, Si. CONSTITUTION:The dielectric film contains one or more of such elements as Ba, Fe, Pb, Sc, Sr, Zn, La, Si and is formed from Ta2O5 containing each element preferably in the range 0.1-10atom%. These elements intrude in lattice defects or educe at the surface of crystal grain boundary to form oxide. This generates insulating property at these defects which might cause leak current, and a Ta2O5 film with less leak current can be accomplished.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to Ta2 used in dRAM, KL elements, etc.
This relates to a dielectric film made of O5.

Conventional technology Conventionally, in order to form a Ta2O5 film, reactive sputtering,
Methods such as CVD were used.

Problems to be Solved by the Invention However, with the above method, in the case of reactive sputtering, it is difficult for oxygen to be absorbed into the film, and lattice defects due to lack of 2-heap oxygen increase, resulting in an increase in leakage current. increases.

Further, when the CVD method is used, there is a problem that the formed film tends to crystallize due to the high temperature of the substrate, and leakage current tends to increase.

In view of this, an object of the present invention is to provide a high quality Ta2O5 film with low leakage current.

Means for Solving the Problems The present invention provides Ba, Fe, Pb, Sc, Sr, Zn, La
, contains at least one element of Si, and each element is preferably contained in a range of 0.1 to 1o aTom%.
The T1L2o5 membrane tissue that is present.

Effect of the present invention The above-mentioned elements enter lattice defects or precipitate on the surface of grain boundaries to form oxides, thereby creating insulation properties in the defects that cause leakage current, thereby reducing leakage current. It is possible to form a Ta2o5 film.

Example As an example of the present invention, Ha is added to a Ta2O5 film 3'
・−・ Describe the case when doing so.

Although any method may be used to incorporate the above elements into the film, reactive sputtering was used this time. The target is Ta 2O5 and BaO with Ba/Ta=1atom
% and sintered. The discharge gas used is a mixture of Ar and 02 at a ratio of 4:1. Silicon (S
l) The substrate temperature of the substrate was set in the range of 200°C to 400°C. The film thickness of Ta2O5 to be formed was fixed at 1Ii30mm, and A7 was used as an electrode. The figure is a cross-sectional view of the LOC:O3 structure capacitor used for leakage current measurement.

5102 on the Si substrate 5 by LOCO8 method (selective oxidation method)
Film 2 was formed, the substrate temperature was set in the range of 200"C to 400°C, and Ba-doped Ta2 was formed by the above sputtering method.
An O5 film 1 is formed. A4 electrode 6 is formed 1 further P-8
Measuring pad user 7 for forming the iO2 film 3 and measuring leakage
! 4, A14 for the measurement band and 1'MA7
! The 5102 film 3 which becomes the interlayer insulating film of 6 is plasma CVD.
5in2 deposited in As a result of the measurement, a decrease in leakage was observed compared to the sample containing no Ba. However, B
If the concentration of a exceeds 10 atom %, the leakage current will increase, so a concentration within this range is desirable. Further, since the amount of the added element was very small, no significant decrease in the dielectric constant was observed. It is thought that the cause of the decrease in IJ current is that the additive element enters glue defects and grain boundaries, thereby compensating for charge imbalance and restoring crystallinity.

Other elements other than Ba may also be used, such as Fe, Pb,
Sc, Sr.

Zn, La, and Si also react with Ta2O to form tantalic acid (
Since it is easy to form a compound with TaO2-), similar effects can be obtained.

In addition, instead of sputtering, Ta2O5 can be produced using CVD method.
Also when forming T2La15 and BaC, Ca14
By reacting with barium chloride and introducing it, Tλ.

Ba can be deposited. Furthermore, since the CVD method has good step coverage, it is advantageous for forming a film inside the trench of a random access memory.

Effect of the invention 5 - As explained above, according to the present invention, T a 2O5
The leakage current is reduced by adding a small amount of elements when forming the dielectric material, and there is no large decrease in dielectric constant due to the addition, so the practical effect of high-quality Ta2O thin film as a dielectric material is great, and it is highly dense and This will greatly contribute to capacitive semiconductor memories and devices that require high dielectric constant dielectric films.

[Brief explanation of drawings]

The figure is a cross-sectional view of a semiconductor device using a dielectric film according to an embodiment of the present invention and used for measuring leakage current. 1...Ta2O5 film (added with elements), 2...SiO□, 3...Plasma 5
102.4,6...jJ electrode, 5...
Si substrate. Name of agent: Patent attorney Toshio Nakao and 1 other person1-
-- TazOg 2---, SSaO2 3-p-sshiO之4---cis11ri [ba, throat MAL S---δi base 5----

Claims (2)

[Claims] (1) Ba, Fe, Pb, Sc, Sr, Zn, La, S
T containing at least one element among the elements of i
A dielectric film made of a_2O_5. (2) Each element at 10^-^3 to 10 atom%
The dielectric film according to claim 1, which contains the dielectric film in the following range.