JP2762910B2 - Luminescent material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a luminescent material, especially a luminescent material in the infrared to visible range. The components of the material can be obtained easily and in large quantities, and the production method is also easy. The visible light-emitting material can be used as various display devices, image display devices such as televisions and computers, and other light-emitting elements.

[0002]

2. Description of the Related Art Conventionally, a direct transition type semiconductor or phosphor has been used as a light emitting material using a bulk material. For example, in a semiconductor material such as GaAs or GaP, the bulk crystal itself has light emission characteristics. These emission wavelengths are specific to the material. The emission wavelength can be changed by forming a mixed crystal. For example, Al _x Ga
_1- xAs can be produced at a wavelength intermediate between the emission wavelengths of GaAs and AlAs.

[0003] Apart from this, rare earth compounds such as CaWO ₄ and MgWO are used as materials which emit light by themselves.
₄ emits intrinsic light when excited electrons fall into the rare earth inner core electrons. In some cases, such as ZnS: Cu, light emission accompanying the light emission center is obtained by introducing the light emission center.

Further, light in the visible region has been obtained from amorphous silicon carbide containing hydrogen and a small amount of oxygen (Japanese Patent Application Laid-Open No. 58-1983).
218114).

[0005] It has been reported that infrared light was obtained at a low temperature with amorphous silicon (K. Morigaki,
Wai Sano, I Hirabayashi, Journal of the Physical Society of Japan (KM
Orinagaki, Y .; Sano. I. Hiraba
yasi, J .; Phys. Soc. Jpn. ) Vol. 5
1, pp. 147-152 (1982)). At this time, it is reported that the emission intensity increases and the peak wavelength changes when the oxygen concentration in the film is increased, but the intensity is weak at room temperature.

[0006]

In the case of a semiconductor light emitting material, the good crystallinity of the material is sensitive to the high luminous efficiency and properties, but it is not easy to produce a material having good crystallinity. The emission wavelength is specific to the material, and many materials that can emit light of a short wavelength in the visible region are particularly difficult to grow crystals.
Further, the production of mixed crystals for wavelength control cannot be achieved at all mixed crystal ratios. Further, when such a material is used, an emission wavelength (range) is determined by a property inherent to the material. That is, it is difficult to obtain a wide emission wavelength range. The emission wavelength of a material using a rare-earth compound or a light-emitting center is also determined by the material. Further, it has been reported that a film containing carbon requires oxygen and hydrogen at the same time in a film produced as an amorphous material, and thus requires a complicated composition. According to a report of a material consisting of only silicon and oxygen, the emission wavelength range is from 7000 angstroms to 6000 angstroms, and the wavelength variable range is narrow. (R. Carius, R. Fischer, E. Holzenkamper, Journal of Luminescence (R. Carius,
R. Fischer, and E.C. Holzenkam
pfer, J.A. Lumines. ) 24/25, 47
(1981)).

An object of the present invention is to provide a light-emitting material which emits strong light even at room temperature in a wide wavelength range including the infrared and visible regions, and which is easily available by using a readily available material. is there.

[0008]

According to the present invention, a luminescent material containing a visible region is characterized by using silicon and one or more materials forming a compound with silicon. Oxygen and nitrogen are used as materials for forming the compound. The structure need not be crystalline. Therefore, the manufacturing method is simple, and the type and state of the substrate to be grown are not limited.

In the present invention, the emission wavelength can be continuously controlled over a wide range by changing the composition.

The substrate on which the light emitting material is made may be any of a metal, a semiconductor substrate, and an insulator substrate. A gas is supplied to deposit silicon. For example, silane (SiH ₄ ) can be used. Nitrogen and oxygen are combined by introducing respective gases as components to be combined with silicon. In order to simultaneously supply oxygen and nitrogen, a compound gas such as N ₂ O gas can be used.

As the reaction chamber, a method capable of dissociating and activating a gas, such as a barrel-type or parallel-plate-type RF plasma discharge device or an ECR plasma ion source, can be used. Since the substrate temperature affects the film quality and the deposition rate, an appropriate temperature is selected for each gas.

The composition ratio of the deposited film changes according to the conditions for producing the deposited film, such as gas pressure, gas flow ratio, substrate temperature, and plasma generation power, so that the emission intensity and emission wavelength can be controlled.
Since the luminescent material of the present invention does not require a perfect crystal, the substrate material is not as problematic as when growing crystals, and has the advantage that a wide variety of substrates can be selected. Deposition rate is substrate temperature,
It can be controlled by the amount of reactant gas supplied, plasma generation power, and the like. When a gas which is easily decomposed by heat is used, the gas can be deposited by a thermal CVD method in which the gas is deposited only by heating the substrate. At this time, the deposition rate can be controlled by the substrate temperature and the amount of supplied reactant gas.

The composition of the film to be deposited is determined by the flow ratio of the supplied reactant gas, gas pressure, substrate temperature, RF power and the like. The composition of the deposited film is, for example, SiOxNy in a combination of silicon, nitrogen and oxygen, where x is 2 or less and y is 1.25 or less. It is possible to change the emission wavelength by preparing a crystal with a composition ratio deviating from a perfect crystal exclusively and changing the composition ratio, for example, x = 0.5 to 1.5 and y = 0.2 to 1. In the case of SiO _x N _{0. 6 x} shown in FIG. 1 as an example. This material has emission peaks in the infrared and visible regions. FIG. 2 shows a change in the position of the emission peak when the flow ratio of the N ₂ O gas and the SiH ₄ gas was changed from 0.5 to 4 when the film was grown. FIG.
It can be seen that the emission wavelength can be controlled by the gas flow ratio. At this time, the composition ratio of the film substantially corresponds to x = 0.5 to 1.0.

In order to increase the luminous efficiency at room temperature, it is generally better to reduce the number of dangling bonds in the film. In the present film, by optimizing the deposition conditions such as the substrate temperature RF power and the gas pressure, dangling bonds can be reduced by mutual bonding of Si, N and O. Also in this film, dangling bonds can be reduced by adding hydrogen. When SiH ₄ gas is used in the present film forming method, hydrogen is simultaneously supplied, and thus has the function of automatically terminating dangling bonds. Additional hydrogen can be added during the deposition to increase the dangling termination efficiency. In that case, it is possible to terminate efficiently by radicalization without adding hydrogen gas as it is.

Depending on the type of reaction gas used and the state of the substrate, selectivity can be given to the deposition rate. For example, when the material of the substrate is different, when the surface treatment is different, when the surface temperature is different, etc., the light emitting material having an arbitrary pattern can be grown by providing selectivity.

The deposited film can emit light by photoexcitation, electron beam excitation or the like. In addition, an electrode can be formed to perform electroluminescence or current injection luminescence. It is easy to make the film quality uniform, and it is possible to make a film having a uniform emission intensity.

The light emitting layer thus manufactured can be easily processed by ordinary lithography and etching processes, and the shape can be freely controlled. Further, since deposition on a semiconductor substrate is possible, application to a display device or the like is easy.

[0018]

According to the present invention, a light emitting material can be obtained by using easily available materials such as silicon, nitrogen and oxygen.

The emission wavelength can be controlled by changing the composition ratio. Where SiO _x N _{0. 6 x} shown in FIG. 1 as an example. This material has emission peaks in the infrared and visible regions. FIG. 2 shows a change in the position of the emission peak when the composition ratio of the N ₂ O gas and the SiH ₄ gas was changed from 0.5 to 4 when this film was grown. FIG. 2 shows that the emission wavelength changes from the infrared region to the visible region by changing the gas flow ratio. At this time, the composition ratio of the film is approximately from x = 0.5 to 1.
Corresponds to 0.

[0020]

【Example】

(Example 1) In this example, a silicon substrate and a quartz substrate were used. Silane (SiH ₄ ) was used as a gas for depositing silicon, and N ₂ O gas was used as a gas capable of simultaneously supplying oxygen and nitrogen.

Using a parallel plate type plasma generator shown in FIG. 4, a high frequency of 13.5 MHz was applied to generate plasma. In FIG. 4, 1 is an RF power supply substrate, 2 is a vacuum chamber, 3 is a luminescent material (deposited film), 4 is a substrate, 5
Denotes a substrate heating holder, 6 denotes a radical generator, 7 denotes a silane gas inlet, 8 denotes an N ₂ O gas inlet, and 9 denotes a hydrogen gas inlet.

The gas pressure was always 30 Pa when SiH ₄ gas and N ₂ O gas were simultaneously supplied. The high frequency power was 280 W. The gas flow rate at this time is N ₂ O
/ SiH ₄ flow ratio is 0.5, N ₂ O gas is 66.6 SC
CM and SiH ₄ gas are 133.3 SCCM. The substrate temperature was 280 ° C.

The deposition rate was 30 n / min. Si
When H ₄ gas is used, hydrogen is supplied at the same time.
It has the function of automatically terminating unjoined hands. Additional hydrogen can be added during the deposition to increase the dangling termination efficiency. In that case, it is possible to terminate efficiently by radicalization without adding hydrogen gas as it is. Annealing in hydrogen after production is also effective.

(Examples 2 to 7) Similar to Example 1, except that the flow rates of N ₂ O gas and SiH ₄ gas were changed.
The gas pressure was always set to 30 Pa when the SiH ₄ gas and the N ₂ O gas were simultaneously supplied, and the flow rate ratio was changed from 0.75 to ₄ for the N ₂ O / SiH ₄ flow rate. Table 1 shows the gas flow ratio at this time.

In the embodiment, the composition of the deposited film was controlled by changing only the gas flow ratio.

[0026]

[Table 1]

FIG. 3 shows H, O, and H in the films of Examples 1 to 7.
The result of having analyzed the volume density of N is shown. Si is 2 × 10 ²²
/ Cm ³ , H is S
i, and the composition ratio of N and O is SiO _x N
_0. When expressed as _{6 x,} corresponds to the x = 0.5 to 1.

FIG. 2 shows the emission wavelengths of Examples 1 to 7. It can be seen that by changing the composition, the emission peak position can be controlled from the near infrared region of 8300 angstroms to the visible region of 6100 angstroms.

[0029]

As described above, the present invention has a wider range of control of the emission wavelength and a wider range of application as compared with the conventional film.
In addition, it is easy to obtain materials, the manufacturing process is simple, the reproducibility is good, and the productivity is increased. In the production of this film, contamination or damage to the substrate is small. In addition, a light emitting layer can be selectively deposited and manufactured.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of an emission spectrum of a light emitting material of the present invention.

FIG. 2 is a diagram showing that the emission spectrum peak of the light emitting material of the present invention can be controlled by the composition.

FIG. 3 is a diagram showing the concentrations of nitrogen, oxygen, and hydrogen when the flow ratio of N ₂ O and SiH ₄ gas is changed.

FIG. 4 is an explanatory view showing an apparatus for manufacturing a light emitting material of the present invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 RF power supply substrate 2 Vacuum chamber 3 Light emitting material (deposited film) 4 Substrate 5 Substrate heating holder 6 Radical generator 7 Silane gas inlet 8 N ₂ O gas inlet 9 Hydrogen gas inlet

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C09K 11/00-11/89 H05B 33/14 C23C 16/30-16/42 C01B 21/068 C01B 21 / 082

Claims (1)

(57) [Claims] 1. A luminescent material comprising only silicon, nitrogen, oxygen and hydrogen, and formed by supplying SiH ₄ gas and N ₂ O gas to a plasma generator.