JPH0226178B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method and monitor for detecting and quantifying Se, and particularly to a method and monitor capable of detecting and quantifying gaseous Se at low temperatures in conventional atomic absorption spectrometry. Regarding. The method and monitor of the invention include:
Semiconductor products and semiconductor manufacturing equipment using Se, waste treatment equipment, such as epitaxial growth equipment (CVD furnace, LPE furnace, etc.) for compound semiconductors such as ZnSe and CdSe, high-pressure HB furnace, annealing furnace, Se pressure annealing furnace, MBE equipment, MOCVD equipment, etc., or Se
A method for detecting and quantifying Se in melting furnaces for alloys, ceramics, glasses, etc. containing , has great effects.

(Prior art) Recently, various industrial fields such as semiconductors, alloys,
Various types of products are used in the production of ceramics, glass, etc.
As Se-containing compounds are developed, highly sensitive detection and quantification of Se is required.
It was based on atomic absorption spectroscopy, which detects the atomic absorption spectrum unique to Se. As shown in Figure 5 [Source: Hamamatsu Photonics Catalog], the atomic absorption spectrum of Se has a sharp peak at a wavelength of 196.03 nm. The general configuration of a conventional atomic absorption spectrometer that utilizes this peak is as shown in FIG. 6, and the light from the light source section 1 is
The light that is incident on the sample atomization section 2 and passes through the atomization section 2 passes through a light selection section (for example, a monochromator) 3 and enters photometry sections 4 to 6 where it is detected and quantified. 4 is a detector, 5 is an amplifier, and 6 is a meter section. In order to atomize Se in the sample atomization section 2, it is necessary to set the atomization temperature to 2000° C. or higher, and flame is generally used as a simple method.

(Problem to be solved by the invention) However, using the above atomic absorption spectrum
Se detection methods require high temperatures (atomization temperature) and are therefore unsuitable for detecting Se at temperatures below the atomization temperature.
There is no detection/quantification method for SeX, and no on-site detection/quantification method or monitoring exists.

In view of the above-mentioned current situation, an object of the present invention is to provide a novel method and monitor for detecting and quantifying Se that enables highly sensitive detection and quantification of Se at temperatures below the atomization temperature, which was previously impossible. .

(Means for Solving the Problems) The present invention detects and quantifies gaseous Se using the absorption spectrum, which the present inventors discovered during their research.

That is, the present invention provides gaseous Se with wavelengths of 324 nm, 326 nm, and 328 nm at a temperature lower than the atomization temperature of Se.
m, 330nm, 332.5nm, 335nm, 337.5nm, 340n
m, 342nm, 344.5nm, 347nm, 350nm, 352.5n
Two or more of the spectral lines of m, 355 nm, 357.5 nm, and 360 nm are incident, and the absorption of the incident spectral lines by the gaseous Se is measured, and Se is detected and quantified from the peak height of the light intensity. This is the way to do it. Furthermore, the present invention provides a window section in the direction in which light travels through the furnace or container with a heater, and one window section has wavelengths of 324 nm, 326 nm, 328 nm, 330 nm,
332.5nm, 335nm, 337.5nm, 340nm, 342nm,
344.5nm, 347nm, 350nm, 352.5nm, 355nm,
357.5nm and 360nm spectral line emission section, and the other window shows Se from the peak height of the light intensity of the spectral line that has passed through the gaseous Se in the container with a heater.
It is connected to a light receiving/photometering section that detects and quantifies the
It is a Se monitor.

Below, the circumstances that led to the present invention and the method and monitor of the present invention will be specifically explained.

Below the atomization temperature, in the temperature range of 220°C to 695°C, Se becomes gaseous Se, and Se ₂ , Se ₄ , Se ₆
It is thought that it exists as such, but it has not been specified [References: O. Kubaschewski et al.
"Metallurgical Thermochemistry"
Pergamonpress (1967)] Regarding this gaseous Se, the present inventors have
We discovered a total of 16 new absorption spectra as shown in Figure 1. The vertical axis in FIG. 1 represents absorbance (arbitrary units), and the horizontal axis represents wavelength (nm). ~
The wavelengths of the peaks numbered are as follows.

324nm, 326nm, 328nm, 330nm,
332.5nm, 335nm, 337.5nm, 340nm,
342nm, 344.5nm, 347nm, 350nm,
352.5nm, 355nm, 357.5nm, 360nm. In the absorption spectrum shown in Figure 1, the 6th wavelength
The peak at 335 nm has the highest absorbance.

The present invention is characterized in that Se can be detected with high sensitivity by selecting two or more of the above-mentioned peaks and measuring them simultaneously. In other words, two or more spectral lines with different wavelengths are incident at the same time, measured separately using a spectrometer in the light emitting part, and then averaged. Separation becomes more reliable, and the accuracy of Se quantification improves.

The method for detecting and quantifying Se of the present invention is carried out in principle with the configuration shown in FIG. In FIG. 2, reference numeral 1 denotes a light emitting unit that emits light corresponding to the wavelength of the peak to be measured among the above-mentioned ~ peaks of gaseous Se. As the light-emitting section, for example, one having a hollow cathode lamp as a light-emitting source and a filter centered on each of the spectral lines .about. is used.

Reference numeral 2 denotes a sample chamber, which has a structure capable of holding Se gas inside, and has a window 3 that lets in at least the incident light from the light emitting part 1, and a window 3 that allows the transmitted light to be absorbed by the Se gas. It is a furnace having a window 4 extending to a light receiving section 5, or a cell having a heating means.

The light receiving section 5 is composed of a usual monochromator, detector, amplifier, meter, etc.

The principle of the detection/quantification method of the present invention is that the peak absorption of ~ in Fig. 1 is determined in proportion to the concentration of gaseous Se. The incident light intensity in the sample chamber
I ₀ , the transmitted light intensity after absorption by gaseous Se is I, the light absorption rate of gaseous Se in the sample chamber is T (%), the absorbance is D, and the concentration of gaseous Se is C, then T ( %)=I/I ₀ ×100 D=log1/T(%) D∝C.

On the other hand, Se input amount and absorbance D, that is, log
It has been found that there is a relationship between 1/T (%) as shown in FIG. In Figure 3, point A is at temperature t.
It represents the saturation point of Se gas, as shown in the following equation:
Specified by the vapor pressure of Se.

logPt (mmHg)=-4990/T+8.09 However, here, T is the temperature on the absolute temperature scale.

(Example) Using an apparatus in which the sample chamber 2 is a cell equipped with a heater 6 as shown in Fig. 4, a sample containing Se is placed in the cell and the temperature is maintained at a constant temperature of 450°C. The spectrum was as shown in FIG.

If you select two or more of the peaks of ~ and measure them separately with a spectrometer and average them, you get
It became possible to detect Se on the order of 0.01 ppm.

(Effects of the Invention) The effects of the Se detection/quantification method of the present invention detailed above are as follows.

(1) Measurements are made using the spectral lines shown in Figure 3 in the vicinity of 335 nm due to the absorption of gaseous Se, which was newly discovered by the present inventors. ) It is possible to detect and quantify Se at low temperatures below.

(2) As mentioned above, detection and
Since it can be quantified, on-site analysis is possible.

(3) Since we use a method of measuring simultaneously at two or more peak wavelengths among the peaks ~ in Figure 1, separation from other substances becomes clear and the accuracy of Se quantification improves (0.01 ppm
(can be detected up to).

(4) The device of the present invention can be used as a monitoring device that can quantitatively detect Se and control the amount of Se introduced and the Se pressure on the spot.

[Brief explanation of drawings]

Figure 1 shows the absorption spectrum of gaseous Se at 450°C, and ~ in the figure indicates the peaks. Figure 2 is a diagram explaining the configuration of the Se detection and quantitative method of the present invention. Figure 3
The figure shows the relationship between Se content and log1/T%, Figure 4 shows the schematic configuration and temperature distribution of an embodiment of the present invention, Figure 5 shows the atomic absorption spectrum of Se, and Figure 6 shows the atomic absorption spectrum of Se.
The figure is a diagram showing a schematic flow of atomic absorption spectrometry.

Claims (1)

[Claims] 1 At a temperature lower than the atomization temperature of Se, gaseous
Se has wavelengths of 324nm, 326nm, 328nm, 330nm,
332.5nm, 335nm, 337.5nm, 340nm, 342nm,
344.5nm, 347nm, 350nm, 352.5nm, 355nm,
Two or more of the spectral lines of 357.5 nm and 360 nm are incident, absorption of the incident spectral lines by the gaseous Se is measured, and Se is detected and quantified from the peak height of the light intensity of the spectral lines. How to do it. 2 A window is provided in the direction of light propagation of the furnace or container with a heater, and one window has wavelengths of 324 nm, 326 nm,
328nm, 330nm, 332.5nm, 335nm, 337.5nm,
340nm, 342nm, 344.5nm, 347nm, 350nm,
emitters of two or more of the 352.5nm, 355nm, 357.5nm and 360nm spectral lines;
The other window shows the peak height of the light intensity of the spectral line that has passed through the gaseous Se in the heater-equipped container.
It is connected to a light-receiving photometer that detects and quantifies Se.
Se monitor.