JPS59216629A - Optical gaseous phase growing method - Google Patents

Abstract

PURPOSE:To utilize anti-stokes light generated by utilizing an energy level of one gas in forming, for example, a membrane by optical reaction by using two or more of reaction gases in exciting the energy state of the other reaction gas. CONSTITUTION:In a photochemical gaseous phase growing method for generating chemical reaction by irradiating two or more reaction gases with light, two lights having different wavelengths are simultaneously made to be irradiated and anti-stokes light is generated by utilizing the energy level of one reaction gas to be utilized in exciting the energy state of at least the other one reaction gas. By this method, because anti-stokes light is generated in a reaction tube by using reaction gases, high vibration light which could not be industrially used from the constraints of a light emitting source and the material of a light pervious window can be used in optical gaseous phase growth.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photo-vapor phase growth method in which a chemical reaction is caused by irradiating a mixed gas of two or more types of gas with light to form, for example, a thin film entirely.

When forming a film by photovapor phase reaction using two or more reactive gases, it is necessary to excite the electronic states of all the reactive gases used to form a thin film with excellent bonding properties. This is a well-known fact. However, the frequency of light required to excite the electronic state is
The amount of light varies greatly depending on the type of reactant gas, and amounts to EiJ' viewing area light, external light, and airborne external light. For this reason, due to restrictions on the light emitting source and the material of the light transmission window, the frequency of 1
．． It is industrially difficult to excite the electronic state of a reaction gas, which requires vacuum ultraviolet light of 62x l Q” Tc or higher.
The same applies to laser light, and the highest frequency of laser light that can be used industrially is the laser light with a frequency of 1.55×10 3 Tc produced by an ArF excimer laser light source. For this reason, industrially, for example, the frequency is 1.62X.
Photovapor phase growth using two reactive gases, one whose electronic state can be excited by light of 10" Tc or less and the other whose electronic state cannot be excited, uses a light source with a frequency of 1.62 Currently, photovapor phase growth is performed by exciting only the state.

Therefore, an object of the present invention is to provide a photovapor phase growth method that eliminates the above-mentioned problems.

The present invention utilizes the energy level of one gas to generate anti-Stokes light in the process of forming, for example, a thin hood by photoreaction using two or more reactive gases. It is characterized in that it is used to excite the energy state of at least one other reaction gas.

According to the present invention, in order to generate anti-Stokes light using a reaction gas in a reaction tube, high-vibration light, which could not be used industrially due to restrictions on the light source and light transmission window material, can be produced. It becomes possible to use it for photo-vapor phase growth.

Here, the principle of the optical vapor phase growth method according to the present invention will be explained.

FIG. 1(5) schematically shows the energy state of reactive gas A, and FIG. 1(B) schematically shows the energy state of reactive gas B. In this Figure 1, al, g are IJyE! in the ground states of reactant gas A1 and reactant gas B, respectively. represents the excited state, hν = g snow - El and hνm =
It is E3*-131. Here, h is the blank constant ν
person, νB is the reactant gas A.

Let νA<νB be the vibration frequency of each of the reaction gases B. Therefore, we focused on the reaction gas A with a small vibration frequency, and the vibration frequency νl(
When irradiated with light of νl>νA), a Stokes process of shi1-shiAniji2 occurs. In this state, if we further irradiate light with the same frequency as Stokes light at 22=νl−ν, we get
Resonantly, it is possible to obtain the anti-Stokes light of C1+C2A-2S1-C2-C3. Here, the vibration frequencies of the two irradiation lights are set as S = S B - S A so that S B = S 3.

If S2=S1-ν is selected, the reactive gas B can be resonantly excited by the anti-Stokes light ν3 using the reactive gas A. The principle of the present invention is to carry out photosynthesis using the reactant gas B excited in this manner and the reactant gas A excited by the Stokes process. Furthermore, instead of the reactive gas A, a non-reactive gas may be used and used only as an excitation source for the reactive gas B.

Next, the present invention will be explained in detail based on examples.

As the present example, we will describe a seri in which silicon aluminum is formed by a photovapor phase epitaxy method based on the present invention using two types of gases, 5li14 gas and Al(CH3)3 gas. The excitation of the electronic state of the Al(CH3) 3 molecule is h!
'A mia, Oe V, and for the SiH4 molecule, h
νB"8.2eV. Therefore, 8A with a small frequency
Anti-Stokes light was generated using the electronic tmk of the (C)is)s molecule, and this light was used to perform resonance excitation of the electronic state of the SiH4 molecule. AA (OHs)3 and S
In this example using two types of gases iH4, the difference in the vibration frequencies of the two molecules ν8-ν or 1-27X10'Tc
It is. The frequency is 1'1, which almost matches this frequency.
= 1.21 x 10" Tc KrF excimer laser light was used. Here, the electronic state of the 8 iH4 molecule has a width due to vibrational rotation, so this difference can be ignored. Also, in order to generate strong anti-Stokes light, The resonance condition ν2=ν1−I
/A=4.8X10zTc was supplied by a dye laser light source.

FIG. 2 shows a conceptual diagram of the apparatus used in this example. 20
1 is a KrF excimer laser light source, and 202 is a dye laser light source. Prisms 203 and 204 of the optical system. The lens 205 and the light transmission window 206 are made of synthetic quartz so that ultraviolet light can pass therethrough.

Further, the two laser beams are configured to be focused on the substrate 207 by an optical system of a prism and a lens. In this example, the intensity of the two laser beams is on the substrate, KrF
V-boo light (νl) is IW/am2, dye laser light (
v2) was performed at 2 W/cm2.

Next, the procedure for forming all seven silicon aluminum films according to this example will be described. The board 207 is attached to the board pedestal 208
After thoroughly evacuating the chamber, pulp 209
+t of 8iH4 gas and Al(CH3)3 gas
When the Jt ratio was introduced at a total of 2/1 and the steady flow of I Torr was stabilized, Kr, fi' laser light source 301, dye laser light source VCX light source, fjb number 1.21X103'
I”c.

4.8Xl O” Tc (7) L/-9-Light and Frith A 203.204° Lens 205 and Light Transmission Window 2
The substrate 207 was irradiated through 06 to form silicon aluminum. Here, the frequency of the dye laser beam is
Resonance condition for generating strong anti-Stokes light νz=4.8
When changing from X102ql c, the specific resistance of silicon aluminum increased by about 10%, confirming the effect of the present invention.

As described above, by generating anti-Stokes light using the excited state of one gas, we can eliminate the excitation of the reaction gas that requires vacuum ultraviolet light and the use of a vacuum ultraviolet light source as described in this example. It can be carried out.

Although this example describes the formation of silicon aluminum by a combination of two reactive gases, SiH4 and Al(CHs)s, the principle of the present invention can be applied to many other optical It can also be applied to vapor phase growth, and the effects of the present invention are significant.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating the principle of the first invention. FIG. 2 is a conceptual diagram of the apparatus used in this example. In FIG. 2, 201...KrF excimer laser light source, 20
2...Dye laser light source, 203...
Prism, 204... Prism, 205...
...Lens, 206...Light transmission window, 207.
... Board, 208 ... Board pedestal, 1st
figure

Claims (1)

[Claims] 2) In the photochemical vapor deposition method in which a reactive gas of Iia or higher is irradiated with light to cause a chemical reaction, the energy level of one reactive gas is utilized by simultaneously irradiating light with two different wavelengths. A patented optical vapor phase growth method in which anti-Stokes light is generated by using the anti-Stokes light, and the anti-Stokes light is used to excite the energy states of at least other reactant gases.