JPH0635651B2 - Method for forming titanium nitride thin film - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for forming a titanium nitride thin film on a sample by using nitrogen ion irradiation and titanium vapor deposition in combination.

[Prior Art] As a method of depositing titanium nitride on a substrate as a sample, a PVD method of dissolving and evaporating titanium in a nitrogen atmosphere of several mTorr to several Torr, and a titanium-based gas such as TiO ₃ are used. There is a CVD method or the like in which nitrogen or a mixed gas of a nitrogen-based gas is reacted at a high temperature of about 1000 ° C. and deposited on the substrate surface.

However, the PVD method has a problem that the adhesion strength of the deposited film on the sample surface is inferior, and the CVD method has a problem that the physical properties of the sample (base material) are changed because the processing is performed at a high temperature.

On the other hand, as a method for solving these problems, a method of forming a titanium nitride thin film on a sample by using nitrogen ion irradiation and titanium vapor deposition in combination has been developed. This will be described with reference to FIG. 1. In a high vacuum atmosphere, a sample 2 mounted on a sample support 1 is irradiated with an ion beam (nitrogen ion beam) 3 from an ion source 4 and , The evaporation material (titanium) 6 from the evaporation source 5 is deposited. As a result, a strong thin film can be formed while reducing the temperature rise of the sample 2.

[Problems to be solved by the invention]

In the method using both nitrogen ion irradiation and titanium vapor deposition as described above, conventionally, as the number of incident nitrogen ions to the sample 2 per unit time increases, the proportion of titanium nitride TiN in the formed thin film increases. Was known.

However, when the number of incident nitrogen ions to the sample 2 is increased, the power consumption of the ion source 4 is increased and the power input to the sample 2 is also increased, resulting in a large temperature rise of the sample 2. Will occur.

Therefore, it is an object of the present invention to provide a titanium nitride thin film forming method capable of increasing the proportion of titanium nitride TiN while solving such problems.

[Means for solving problems]

According to the titanium nitride thin film forming method of the present invention, as a condition for forming the thin film, the ratio N / Ti of the number of incident nitrogen ions to the sample per unit time to the number of incident titanium atoms is N / Ti ≦ 1.
0, the atmosphere nitrogen gas pressure of the sample at that time is 5 × 10 ⁻⁵
The region of 2 × 10 ⁻⁴ Torr, the number of incident titanium atoms to the sample is 3 × 10 ^{22 to} 3 × 10 ²³ atoms / cm ² , and the energy of nitrogen ions is 10 to 30 KeV.

[Action]

Under the above-described conditions, the ratio N between the number of incident nitrogen ions and the number of incident titanium atoms per unit time N
Even if / Ti is 1 or more, titanium nitride is formed to a level equal to or higher than the conventional one.

〔Example〕

Also in this embodiment, an apparatus having the same structure as that shown in FIG. 1 is used. In this case, for example, titanium vapor deposition uses an electron beam heating evaporation source, and nitrogen ions use the ion beam as it is extracted from the ion source. Then, the titanium evaporation amount is defined by the electron beam power of the evaporation source, and the nitrogen ion beam amount is defined by the pressure of the nitrogen gas introduced into the ion source and the power of arc discharge generated in the ion source. In addition, nitrogen gas is supplied to the atmosphere of the sample.

Then, as a condition for forming a thin film, the ratio N / Ti of the number of incident nitrogen ions to the sample per unit time to the number of incident titanium atoms is N / Tl ≦ 1.0, and the atmospheric nitrogen gas pressure of the sample at that time Is 5 × 10 ^{−5 to} 2 × 10 ⁻⁴ Torr, and the number of incident titanium atoms to the sample is 3 × 10 ^{22 to} 3 × 10 ²³ per second.
/ Cm ² , the energy of nitrogen ions is 10 to 30 KeV
Use the area of.

Under the above conditions, the ratio of the number of incident nitrogen ions to the sample per unit time and the number of incident titanium atoms (ratio of the number of incident particles) N / Ti to titanium nitride and titanium oxide in the formed thin film The result of measuring the ratio TiN / TiO by X-ray photoelectron spectroscopy (XPS) is shown in FIG. N / Ti> 1
The area of 1 is obtained by the conventional method, and the area of N / Ti≤1 is obtained by the method of the present invention.

Conventionally, it was known only that the proportion of titanium nitride TiN in the formed thin film increased as the number of incident nitrogen ions increased, but as a result of various experiments this time, the number of incident particles was increased under the above conditions. It has been found that even if the ratio N / Ti is less than or equal to 1, the target titanium nitride TiN is formed to be equal to or more than the conventional one.

In this case, the required number of nitrogen ions can be reduced under the condition that the ratio N / Ti of the number of incident particles is N / Ti ≦ 1.0, which allows the power consumption of the device, specifically, the ion source to be reduced. Can be reduced.

Further, along with this, the power applied to the sample at the time of forming the thin film can be reduced, so that the temperature rise of the sample can be suppressed and the change in the physical properties thereof can also be suppressed. In addition, since the restrictions from the sample are reduced by this, the range of application of this thin film forming method can be greatly expanded, and it becomes possible to form a thin film on, for example, plastic, silicon rubber, polymer film, or the like.

Furthermore, since the thickness of the thin film to be formed is determined by titanium, it is necessary to increase titanium when increasing the thickness,
As can be seen from FIG. 2, in the present invention, unlike the prior art, if the amount of titanium is increased, the ratio N / Ti of the number of incident particles is decreased and the target titanium nitride TiN is increased. Can be formed quickly, which improves productivity.

〔The invention's effect〕

As described above, in the present invention, it is possible to increase the proportion of titanium nitride TiN in the formed thin film to a level equal to or higher than the conventional one, reduce the power consumption of the device, and suppress the temperature rise of the sample. You can also Furthermore, the productivity of the thin film can be improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an apparatus used for a titanium nitride thin film forming method using both nitrogen ion irradiation and titanium vapor deposition. FIG. 2 is a diagram showing the measurement results of the ratio TiN / TiO of titanium nitride and titanium oxide in the formed thin film with respect to the ratio N / Ti of the incident number of nitrogen ions and titanium atoms during thin film formation. 2 ... sample, 4 ... ion source, 5 ... evaporation source

Claims (1)

[Claims] 1. A method for forming a titanium nitride thin film on a sample by using nitrogen ion irradiation and titanium vapor deposition in combination, the conditions for forming the thin film are as follows: the number of incident nitrogen ions and the number of incident titanium atoms per unit time on the sample. And the ratio N / Ti is N
/Ti≦1.0, the nitrogen gas pressure in the sample atmosphere is 5 ×
10 ^{−5 to} 2 × 10 ⁻⁴ Torr, the number of incident titanium atoms to the sample is 3 × 10 ^{22 to} 3 × 10 ²³ atoms / cm ² ,
A method for forming a titanium nitride thin film, characterized in that a region of nitrogen ion energy of 10 to 30 KeV is used.