JPS6117032A - Microscope-laser raman spectrometer - Google Patents

Abstract

PURPOSE:To determine the azimuth of a crystal without contact and without destruction quickly, by providing a variable aperture, whose light converging solid angle can be varied arbitrarily, in an optical path of scattered light, which is converted by an objective lens having sufficiently large numerical aperture. CONSTITUTION:Light is converged at a large solid angle by an objective lens having sufficiently large numerical aperture. Then the light converging solid angle is variably adjusted by a variable aperture 5. The scattered light, which is transmitted through the variable aperture 5, is guided to a spectroscope 10 through following optical systems 6, 7, 8 and 9. In order to change the conditions of polarized light, a 1/2 wavelength plate 11 and a polarizing filter 12 are provided. Light intensities YY, YX, XY and XX are measured in this way. Thus the scattered light in an arbitrary solid angle can be divided, and the azimuth of a crystal can be quickly determined without contact and without destruction.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a microlaser Raman spectroscopy device that enables crystal orientation determination.

(Prior art and its problems) In recent years, with the aim of increasing the speed of integrated circuits and making them three-dimensional, technology for creating silicon films on insulators (SOI) has been developed, and devices are now at the stage of being prototyped. There is. The main defects in SOI are cracks and grain boundaries, and their reduction has become an extremely important issue.

Another problem is the control of crystal orientation of silicon grains recrystallized by laser etc.
For this purpose, it is necessary to quickly measure the orientation of recrystallized grains in a non-destructive and non-contact manner. Conventionally, the fcX111 diffraction method and the electron channeling method (ECP method) that have been used for this purpose have the disadvantage that they can only obtain signals from a large area or only from the very surface layer. was there.

(Objective of the Invention) The present invention improves a microlaser Raman spectrometer that uses a focused laser beam as a probe, making it possible to determine not only the strain inherent in crystals such as SOI but also their crystal orientation. It is intended to be.

(Structure of the Invention) According to the present invention, in a microlaser Raman spectrometer that narrows down the excitation laser beam and irradiates the sample, and collects the emitted Raman scattered light into 11 minutes; A microscope characterized in that a variable aperture is provided in the optical path of the scattered light that can arbitrarily change the solid angle of convergence, thereby making it possible to separate the scattered light within any solid angle and determining the crystal orientation. A laser Raman spectrometer is obtained.

(Detailed Description of Configuration) The present invention solves the problems of the prior art by adopting the above-described configuration.

Conventionally, Vl'- is mainly measured by laser Raman spectroscopy.
Appl, Phys-Lett, 44 (19
84) and 535), in which measurement is performed by changing the polarization direction of the incident angle, but this method has the disadvantage that correction is complicated.

The present invention focuses on the directionality of scattered light, and provides a variable aperture in the optical path in order to change the solid angle of convergence over an extremely large range.

'An example of the basic configuration is shown in Figure 1.

1 in the figure indicates the entire excitation laser beam, which passes through the half mirror 2 and the objective lens 3 and is focused onto the sample 4 to a diameter of about 11 tm. Raman scattered light is shown as a dotted line in the figure,
After condensing light at a large solid angle using an objective lens with a large numerical aperture, the condensing solid angle is variably adjusted by the variable aperture 5. Although it is not limited to this position, the position of the diameter of the objective lens is not preferable because it causes problems in convergence of the excitation laser beam, and the position where the diameter of the objective lens is widened is preferable so that the solid angle can be effectively varied. The scattered light that has passed through the variable aperture is guided into the spectrometer 10 through the following optical systems 6, 7, 8, and 9. A % wavelength plate is used to change the polarization conditions. 11, a polarizing filter 12 is additionally required, which allows YY
Measure the light intensity of box α and XX, respectively.

(Example) Using 488 OA light from an Ar ion laser as excitation light, the SOI of a recrystallized Si/510 g/Si structure in which Po7ySi was recrystallized using a rod-shaped heater was measured. As an objective lens, numerical aperture is 0.9 and magnification is 10.
When a 0x lens is used, the laser beam is converged to Lc+m, and the scattered light can be extracted while confirming the irradiation position. The configuration is almost the same as that shown in FIG.
A sample image observation optical system is added to the top of the unit. The variable aperture 5 uses a so-called variable aperture whose diameter can be varied from 4 mm to 0.5 qn. With a diameter change in this range, the numerical aperture effectively changes from 0.9 to 0.2,
Moreover, no decrease in observation image magnification occurs. Due to this change in the numerical aperture, the rate at which directional Raman scattered light is collected changes, and the YY, YX, XY, and XX light intensities also change.

In order to actually determine the orientation, a numerical calculation using this value is required, but it is sufficient to perform this numerical calculation once using the necessary parameters, and the analysis procedure is , is simple enough.

The grain orientation is Euler angle α, β from the laboratory coordinate system.

Bs=M(α, β, γ)Rz−M(α, β, γ)・Ei
becomes. Considering that scattered light has directionality, if we collect only the backscattered light that falls within a specific solid angle, Y
X! =;

Measurements are made under several different NA conditions, and calculations are performed while changing α, β, and γ, and those that match are selected.

In the above sample, the direction K in which the rod-shaped heater was scanned
<100) direction, with a slight inclination in the direction perpendicular to the surface. The variable aperture diameter greatly improves the accuracy of orientation determination.

(Effects of the Invention) As described above, the present invention has made it possible to quickly determine the orientation of a crystal in a non-contact and non-destructive manner.

Furthermore, the target crystal is not limited to Si; crystals with other symmetries can also be used if numerical calculations are performed using the Landzl specific to the crystal.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of the basic configuration of the present invention.
is an excitation laser beam, 2 is a half mirror, 3 is an objective lens, 4
1-j: Sample, 5 is a variable aperture, 6 is a lens, 7 is a mirror, 8 is a pinhole, 9 is a coupling lens, 10 is a spectrometer, 11 is each wavelength plate, and 12 is a polarizing filter gold. -eyes

Claims (1)

[Claims] In a microlaser Raman spectrometer that narrows down the excitation laser beam and irradiates the sample, and then collects and spectrally spectra the emitted Raman scattered light, an objective lens with a sufficiently large numerical aperture focuses the scattered light into an optical path. A microlaser Raman spectrometer characterized by having a variable aperture that can arbitrarily vary the solid angle.