JPS6232607A - Growth and analysis instrument - Google Patents

Abstract

PURPOSE:To simultaneously prevent window contamination during growth, and further, to conduct surface analysis during growth, by providing a growth structure in a vacuum chamber equipped with a radiation window and a laser window, and, in addition, by providing a structure for cleaning the surface of the radiation window. CONSTITUTION:The radiation window 1 introducing radioactive rays for analysis is an X-ray source ray window of a generally used photospectroscope, having Al and Mg targets. A laser window 2 and mirrors 6 and 7 are located in a vacuum chamber 3 so as to irradiate the laser beam having a wavelength of 5,145Angstrom with an incidence angle of 60 deg., generated from an Ar ion laser 5 into the radiation window 1. Since the As beam flow rate for Ga is at least 50 times greater during GaAs growth, amorphous or metallic As adheres to the vacuum chamber 3. When GaAs growth is performed for 100hr or more and the laser beam irradiates radiation window (X-ray window) 1 to the state where the Ga peak strength is reduced to 70% of the initial strength and the laser beam strength become 10<3>W/cm<3> or more, the Ga peak strength increases. Through the laser beam irradiation, As adhering to the radiation window 1 selectively absorbs the laser beam, its temperature increases, and then re-evaporation occurs.

Description

[Detailed Description of the Invention] [Summary] The radiation window through which radiation for analysis is introduced in the growth/analysis apparatus that shares a vacuum chamber becomes contaminated and cloudy due to adhesion of growth substances, and therefore needs to be cleaned. Therefore, we propose an apparatus equipped with a mechanism that can remove contamination by heating with a laser beam.

r Industrial application field] This invention relates to a growth/analysis device equipped with a purification mechanism.

Conventionally, growth substances adhered to the radiation window and attenuated the radiation transmittance, so growth and analysis were performed in separate vacuum chambers, making immediate analysis impossible. Therefore, there is a need for an apparatus that can perform analysis simultaneously during growth.

[Conventional technology]

FIG. 2 is a conceptual cross-sectional view illustrating the configuration of a conventional growth/analysis apparatus.

In the figure, 21 is a growth chamber, 22 is an analysis chamber, and 23 is a sample movement chamber having a sample movement mechanism.

In the above configuration, when analyzing a sample, it was necessary to interrupt the growth and move the sample to the analysis chamber 22 via the sample transfer chamber 23.

The reason why analysis and growth could not be performed in the same vacuum chamber was because, as mentioned above, the growth material adhered to the radiation window through which radiation for analysis was introduced, attenuating the transmittance of the radiation.

[Problem that the invention seeks to solve]

To enable immediate analysis, if analysis and growth were performed in the same vacuum chamber, the growth material would adhere to the emission window and attenuate the radiation transmittance.

[Means for solving problems]

The solution to the above problem is to provide a growth mechanism (4) within a vacuum chamber (3) having a radiation window (1) for introducing radiation for analysis and a laser window (2) for exclusively transmitting laser light. and,
Laser light is guided from the outside through the laser window (2) into the vacuum chamber (3) and irradiated onto the emission window (1) to selectively remove contaminants on the surface of the emission window (1). This is achieved by the growth and analysis apparatus according to the present invention, which has a mechanism for cleaning the surface of the emission window (1) by evaporating the contaminants by heating to .

[Effect]

(11) Since the optical absorption coefficient of contaminants adhering to the emission window surface is high, the laser beam is selectively absorbed there; (2) The thermal conductivity of the window glass is low, so the laser beam The temperature rises locally only in the area that is irradiated with the laser beam, and (3) furthermore, many contaminants are easily evaporated (e.g., phosphorus, arsenic, etc. have high vapor pressure). A mechanism was installed to remove contamination by irradiation.

〔Example〕

FIG. 1 is a conceptual cross-sectional view illustrating the structure of the growth/analysis apparatus of the present invention.

In the figure, 1 is a radiation window that introduces radiation for analysis.
This is the window of the X-ray source of a commonly used photoelectron spectrometer, which has aluminum (Al) and magnesium (Mg) targets.

In order to irradiate the radiation window 1 with the light emitted from the argon (8R) ion laser 5 with a wavelength of 5145 at an incident angle of 60°,
A laser window 2 and a mirror 6.7 were placed in the vacuum chamber 3.

8 is a shutter.

4 is a cell for molecular beam epitaxial (MBE) growth of gallium arsenide (GaAs).

In this apparatus, MBE growth of GaAs and photoelectron spectroscopy were performed to confirm the effects of the present invention.

When growing GaAs, the flow rate ratio of the As beam to Ga is usually as large as 50 times or more, so that amorphous or metallic As adheres to the inside of the vacuum chamber 3.

X-ray electron spectroscopy measures Ga2p3 using the excitation line (Kα) of AI.
/2 level (binding energy 1115 eV).

GaAs was grown for more than 100 hours, and the emission window (X-ray window) was irradiated with a laser beam while the Ga peak intensity (I G-) was reduced to 70% of the initial intensity CrG-0).

FIG. 3 is a diagram showing the relationship between the laser power density irradiated onto the emission window and the Ga peak intensity ratio (I c-/I c-0).

Here, the laser beam irradiation time is 10 minutes.

From the figure, an increase in the intensity of the Ga peak is seen when the laser beam intensity increases to 10:1W/cm2 or more, and 10'W/cm2 or more is observed.
The intensity ratio is improved to 95% with irradiation of cm2.

This is considered to be because, before the laser beam irradiation, a part of the As beam during growth adhered to the emission window 1, absorbed the AIKα excitation line, and reduced the excitation line intensity of the sample.

This example shows that by irradiating the laser beam, As adhered to the emission window 1 selectively absorbed the laser beam, increasing the temperature and causing re-evaporation.

Although the embodiments have been described with respect to materials containing As, the present invention is naturally effective against contamination caused by materials containing other elements with high vapor pressure instead.

〔Effect of the invention〕

As described in detail above, according to the present invention, it is not only possible to clean the emission window after growth, but also to prevent contamination of the window by irradiating the window with laser light during growth. Furthermore, it becomes possible to perform surface analysis simultaneously during growth.

[Brief explanation of drawings]

Figure 1 is a conceptual cross-sectional view explaining the configuration of the growth/analysis apparatus of the present invention, Figure 2 is a conceptual cross-sectional view explaining the configuration of a conventional growth/analysis apparatus, and Figure 3 is a conceptual cross-sectional view explaining the configuration of the growth/analysis apparatus of the present invention. FIG. 3 is a diagram showing the relationship between the irradiated laser power density and the Ga peak intensity ratio (r, , / I G,,). In the figure, 1 is a radiation window that introduces radiation for analysis; 2 is a window for the X-ray source of the photoelectron spectrometer; 3 is a vacuum chamber; 4 is a cell for GaAs MBE growth; 5 is argon ion laser, 6.7 is mirror, 8 is shank

Claims (1)

[Claims] A growth mechanism (4) is provided in a vacuum chamber (3) having a radiation window (1) for introducing radiation for analysis and a laser window (2) for introducing laser light, and , leading a laser beam from the outside through the laser window (2) into the vacuum chamber (3) and irradiating the emission window (1);
Growth and analysis characterized by having a mechanism for selectively heating contaminants on the surface of the emission window (1) to evaporate the contaminants and clean the surface of the emission window (1). Device.