JP5389586B2 - Semiconductor thin film crystallinity evaluation method and crystallinity evaluation apparatus - Google Patents

Description

  The present invention relates to a method and apparatus for evaluating the crystallinity of a semiconductor thin film.

  In recent years, as a thin film transistor (hereinafter referred to as TFT) used in a liquid crystal display device, a polycrystal is used instead of a conventional amorphous silicon semiconductor transistor (a-Si TFT) using an amorphous silicon (a-Si) thin film. A polycrystalline silicon semiconductor thin film transistor (p-Si TFT) using a silicon (p-Si) thin film is used. The p-Si TFT is a silicon semiconductor thin film having a high electron mobility, and can realize high definition, high image quality, and high response speed of a liquid crystal display device.

  The p-Si thin film used for the p-Si TFT is formed on the surface of a glass substrate or the like used for a liquid crystal display device. As a method for forming a p-Si thin film on the surface of the base material, a method is used in which an a-Si thin film previously formed on the surface of the base material is melt-crystallized to change to a p-Si thin film. An excimer laser annealing method (excimer laser anneal method: hereinafter referred to as ELA method) in which an a-Si thin film is melted and crystallized to change into a p-Si thin film is irradiated with an excimer laser for annealing. Is often used. However, the crystal structure such as the crystal grain size and crystal orientation of the p-Si thin film obtained by the ELA method depends on the manufacturing conditions such as the variation in the thickness of the a-Si thin film formed in advance and the pulse fluctuation of the excimer laser to be irradiated. fluctuate. Therefore, in order to obtain a stable product with high yield in the manufacture of p-Si thin films, the crystallinity of the obtained p-Si thin films is evaluated on-line in the production line in a short time, and the results are obtained. There has been a demand for prompt feedback to the manufacturing conditions of the p-Si thin film.

  As a method for evaluating the crystallinity of a p-Si thin film, a method using an X-ray diffraction method, Rutherford backscattering method, transmission electron diffraction method, or the like has been conventionally known. Because it is a destructive test that requires a relatively long time for measurement or that requires the preparation of measurement data by destroying the measurement object, it is difficult to evaluate online in a production line in a short time. As a result, it was difficult to quickly feed back the evaluation results to the manufacturing conditions.

  Further, as in Patent Document 1, a method for evaluating the crystallinity of a silicon semiconductor thin film using Raman spectroscopy is known.

  The method for evaluating the crystallinity of a silicon semiconductor thin film using Raman spectroscopy is excellent in that it does not require destruction of the measurement target. However, the intensity of Raman scattered light detected by the crystallinity evaluation method using Raman spectroscopy is very weak. Therefore, in order to obtain an accurate evaluation result, it is necessary to integrate the measurement results by a plurality of measurements, which is an insufficient measurement method from the viewpoint of obtaining an accurate evaluation result quickly. In particular, it is unsuitable as a method employed for evaluating a formed thin film on-line on a production line and quickly feeding back the evaluation result to production conditions.

  As a method for solving the above problems, a microwave photoconductive decay method (hereinafter referred to as a μ-PCD method) is known. In the μ-PCD method, photoexcited carriers are generated in the semiconductor by irradiating the semiconductor thin film with pulsed excitation light, and then the semiconductor thin film is evaluated at a decreasing rate when the photoexcited carriers are recombined. Is what you do. The decrease rate of the photoexcited carriers can be obtained by irradiating microwaves to the range of the semiconductor thin film including the range irradiated with the excitation light and measuring the reflected light intensity. By adopting such a μ-PCD method, crystallinity can be evaluated quickly without destroying the p-Si thin film.

  However, in recent years, due to the increase in the size of the substrate accompanying the increase in the size of the liquid crystal display device, it has become difficult to evaluate the semiconductor thin film on-line in the production line by the μ-PCD method. This is because a large base material needs to be evaluated (measured) for crystallinity at a plurality of locations in order to ensure the quality of the semiconductor thin film formed on the base material. That is, on-line inspection of a large substrate requires a large number of measurement sites to be measured in a short time, but in the μ-PCD method, the intensity of the reflected wave of the microwave from the semiconductor thin film is weak. Since the measurement sensitivity is low and it is difficult to shorten the measurement time at each measurement site, it is difficult to perform online inspection.

  Therefore, in the evaluation of crystallinity, there is a μ-PCD method in which a dielectric such as a glass plate is arranged between a base material and a sample table on which the base material is arranged to increase the measurement sensitivity. It has been developed. According to this method, since the crystallinity can be evaluated at high S / N at the measurement site, the measurement time at each measurement site can be shortened, and as a result, on-line in the production line for large-sized substrates. Inspection became possible.

JP 2004-226260 A

  When measuring by placing a dielectric between the substrate and the sample stage as in the above measurement method, if dust or the like enters between the substrate and the dielectric or between the dielectric and the sample stage. An air gap is generated, which causes measurement errors. In the measurement method, the dielectric may break due to dust or the like entering between the base material and the dielectric or between the dielectric and the sample table.

  Therefore, in the above measurement method, when setting the base material on the sample stage, dust or the like does not enter between the base material and the dielectric and between the dielectric and the sample stage. It was necessary to work with great care in an extremely strictly controlled environment, and the work of setting the base material on the sample stage was very troublesome and time consuming.

  Therefore, in view of the above problems, the present invention is capable of evaluating the crystallinity of a semiconductor thin film formed on the substrate with high sensitivity while the substrate is easily arranged on the sample stage. It is an object to provide an evaluation method and a crystallinity evaluation apparatus.

Accordingly, in order to solve the above-mentioned problems, the present invention is a method for evaluating the crystallinity of a semiconductor thin film formed on a base material, and the base material is formed on the arrangement surface of a sample stage. An arrangement step of arranging the surface opposite to the surface opposite to the surface formed; an excitation light irradiation step of irradiating excitation light for exciting carriers to the semiconductor thin film on the substrate arranged on the sample stage; A microwave irradiation step of irradiating a microwave having a specific wavelength to a range of the semiconductor thin film including a range irradiated with the excitation light in the excitation light irradiation step, and a reflected wave of the microwave from the semiconductor thin film a measuring step of the intensity of the measuring, the microwave wavelength of the microwave by microwave irradiation with the advance wave is changed in a predetermined range before performing the microwave irradiation step in the semiconductor thin film And a acquisition step of acquiring information on the relationship between the signal intensity of the definitive reflected wave, in the microwave irradiation process, the wavelength of the microwave is determined to actually irradiate on the basis of the information in the acquisition step, The microwave irradiated in the microwave irradiation step is 4n / (1 + 2N) times (n) the distance from the surface of the semiconductor thin film to the arrangement surface of the sample table on which the substrate on which the semiconductor thin film is formed is arranged. : refractive index of the substrate, N: wavelength of 0 or any positive integer) lambda, or, the microwave having a wavelength of the approximate a wavelength approximating to the wavelength lambda when irradiating the semiconductor thin film Indeed the magnitude of the signal intensity of the intensity change due to the excitation light of the resulting reflected wave is to signal strength that obtained when the microwaves with the wavelength λ is irradiated on the semiconductor thin film 9 0 %that's all It characterized by having a wavelength which approximates to the wavelength λ to the extent that a.

  In this way, by placing the substrate directly on the placement surface of the sample stage, it is only necessary between the substrate and the placement surface to pay attention to the entry of dust etc. during placement. Compared with the case where a dielectric is interposed between the base material and the sample table, the arrangement of the base material on the sample table becomes easier.

  In addition, the distance from the surface of the semiconductor thin film to the arrangement surface of the sample table on which the substrate on which the semiconductor thin film is formed is arranged is 4 n / By irradiating a semiconductor thin film with a microwave having a wavelength λ of (1 + 2N) times or a wavelength close thereto, the crystallinity evaluation is highly sensitive (ie, high even if the intensity of the reflected wave from the semiconductor thin film is weak) S / N). Here, n is the refractive index of the substrate, and N is 0 and a positive integer.

  In other words, the standing wave formed by the interference between the microwave irradiated to the semiconductor thin film and the microwave reflected on the arrangement surface is the measurement site (surface) of the semiconductor thin film at the position (antinode) having the largest amplitude. As a result, the intensity change (signal intensity) caused by the excitation light irradiation in the reflected wave of the microwave becomes the largest. If such a large signal intensity is obtained, the crystallinity can be evaluated with high sensitivity even if the intensity of the reflected wave is weak. Therefore, in order to obtain a signal intensity sufficient for evaluation of crystallinity, the wavelength λ at which the maximum signal intensity is obtained, or the wavelength λ to the extent that a signal intensity of 90% or more of the maximum signal intensity is obtained. By irradiating a semiconductor thin film with a microwave having a wavelength close to that of the crystal, the crystallinity can be evaluated with high sensitivity (ie, high S / N) without interposing a dielectric between the substrate and the sample stage. Thus, sufficient crystallinity can be evaluated in a short time.

In the method for evaluating crystallinity of a semiconductor thin film according to the present invention, the microwave is irradiated by irradiating the semiconductor thin film while changing the wavelength in a predetermined range in advance before performing the microwave irradiation step. An acquisition step of acquiring information about the relationship between the wavelength and the signal intensity of the reflected wave in the microwave; and in the microwave irradiation step, the wavelength of the microwave that is actually irradiated based on the information in the acquisition step Therefore, the wavelength of the microwave to be irradiated in the microwave irradiation process can be easily determined .

  In the microwave irradiation step, the measurement microwave is irradiated to the irradiation range of the excitation light and outside the irradiation range of the excitation light, respectively, and the measurement step includes out of the irradiation range from a reflected wave from the irradiation range. It is preferable to have a differential signal deriving step for deriving a differential signal obtained by subtracting the reflected wave from the signal and a differential signal measuring step for measuring the intensity of the differential signal derived in the differential signal deriving step.

  In this case, the crystallinity can be evaluated with higher accuracy than in the case where only the semiconductor region including the irradiation range of the excitation light is irradiated with the microwave and the reflected wave is measured. That is, on the semiconductor thin film, a reflected wave at a site where carriers are generated by irradiation of excitation light and the reflectance of the microwave is increased, and a reflected wave at a site where excitation light is not irradiated and the reflectance is not changed. By measuring the intensity of the differential signal derived from the two reflected waves, it is possible to measure the fluctuation of the intensity of the weak reflected wave from the semiconductor thin film with higher sensitivity.

  Further, in order to solve the above-mentioned problems, the present invention is an apparatus for evaluating the crystallinity of a semiconductor thin film formed on a substrate, and has an arrangement surface, and the substrate is disposed on the arrangement surface. A sample stage to be disposed; excitation light irradiating means for irradiating a semiconductor thin film on a substrate disposed on the sample stage with excitation light for exciting carriers; and the semiconductor including a range irradiated with the excitation light. Microwave irradiation means for irradiating a range of the thin film with microwaves, microwave measurement means for measuring the intensity of the reflected wave of the microwave from the semiconductor thin film, and the measurement value based on the measurement value of the microwave measurement means An evaluation means for evaluating the crystallinity of the semiconductor thin film; and an output means for outputting the evaluation of the crystallinity of the semiconductor thin film evaluated by the evaluation means. The microwave irradiation means is a microwave that emits microwaves. Radiation part A wavelength adjusting unit that changes a wavelength of the microwave radiated from the microwave radiating unit, and a control unit that controls the wavelength adjusting unit, and the control unit is configured to emit the microwave by the wavelength adjusting unit. A first indicator that radiates a microwave while changing the wavelength of the portion; a wavelength of the microwave obtained by the radiation; and an intensity change caused by excitation light of a reflected wave from a semiconductor thin film in the microwave A storage unit that stores a relationship with a signal intensity that is a magnitude, and the microwave radiation by the wavelength adjustment unit based on the relationship between the wavelength of the microwave stored in the storage unit and the signal intensity of the reflected wave. And a second indicator that radiates microwaves having a predetermined wavelength.

  According to such a configuration, a signal intensity large enough to evaluate crystallinity can be obtained without interposing a dielectric between the base material and the arrangement surface of the sample stage, thereby reducing the intensity of the reflected wave. Even if it is weak, crystallinity can be evaluated with high sensitivity (that is, high S / N), and sufficient crystallinity can be evaluated in a short time.

  That is, the first indicating unit changes the wavelength while irradiating the semiconductor thin film on the substrate with the microwave, and the reflected wave is measured to determine the relationship between the wavelength of the microwave stored in the storage unit and the signal intensity. On the basis of this, by irradiating the microwave radiating part with microwaves at a predetermined frequency such that the second indicator can obtain a large signal intensity, a signal intensity sufficient for evaluating crystallinity can be obtained in the measuring means.

  In addition, since the crystallinity can be evaluated with high sensitivity without arranging a dielectric, the substrate can be arranged directly on the arrangement surface of the sample stage, which makes it possible to remove dust and the like during the arrangement. Since it is only necessary to pay attention to the intrusion between the substrate and the mounting surface, it is necessary to pay attention to the entrance to the sample table as compared with the conventional case where a dielectric is interposed between the substrate and the sample table. Arrangement of materials becomes easy.

  Furthermore, the result of the evaluation of the semiconductor thin film is output by the output means, so that the evaluation result can be quickly fed back to the manufacturing conditions in the semiconductor thin film manufacturing line.

  In the semiconductor thin film crystallinity evaluation apparatus according to the present invention, the excitation light irradiating means modulates the intensity of the excitation light radiating section that emits the excitation light and the excitation light emitted from the excitation light radiating section at a predetermined period. A first extraction unit that extracts a periodic component synchronized with the intensity modulation of the excitation light from the modulation unit from the reflected wave of the microwave from the semiconductor thin film. And a periodic signal measuring unit that measures the intensity of the periodic signal extracted by the first extracting unit.

  According to such a configuration, it is possible to measure the signal intensity with high sensitivity by extracting the periodic component synchronized with the intensity modulation from the reflected wave, and measuring this, thereby reducing the size of the excitation light emitting unit. Is possible. That is, by extracting the periodic component synchronized with the intensity modulation from the reflected wave and measuring its intensity, it is possible to measure the fluctuation of the intensity of the weak reflected wave from the semiconductor thin film with high sensitivity. Therefore, the crystallinity can be evaluated with the same degree of accuracy even when a small excitation light emitting unit having a small output is used, compared with a configuration in which excitation light is irradiated without intensity modulation. On the other hand, crystallinity can be evaluated with higher accuracy when using an excitation light emitting section having the same output as that of the configuration without intensity modulation.

  The microwave irradiating means is configured to irradiate the microwave to the irradiation range of the excitation light and the irradiation range of the excitation light, respectively, of the semiconductor thin film, and the microwave measurement means A differential signal deriving unit for deriving a differential signal obtained by subtracting the reflected wave of the microwave from outside the irradiation range from the reflected wave of the microwave from the range, and the differential signal derived by the differential signal deriving unit It is preferable to have a differential signal measuring unit that measures the intensity.

  According to such a configuration, on the semiconductor thin film, the reflected wave at the site where the carrier is generated by the irradiation of the excitation light and the reflectance of the microwave is increased, and the reflectance not irradiated with the excitation light is not changed. By measuring the intensity of the differential signal derived from both the reflected wave and the reflected wave at the site, it becomes possible to measure the fluctuation of the intensity of the weak reflected wave from the semiconductor thin film with high sensitivity. Crystallinity can be evaluated with high accuracy.

  Note that, in the case of a configuration in which microwaves are irradiated to the irradiation range of the excitation light and outside the irradiation range, the excitation light is intensity-modulated at a predetermined period, and a periodic component synchronized with the intensity modulation is extracted from the reflected wave. Is more preferably measured. Specifically, the excitation light irradiation means includes an excitation light emitting unit that emits the excitation light, and a modulation unit that modulates the intensity of the excitation light emitted from the excitation light emitting unit with a predetermined period, The microwave irradiation unit further includes a second extraction unit that extracts a periodic component synchronized with the intensity modulation of the excitation light in the modulation unit from the differential signal derived in the differential signal deriving unit, and the difference The dynamic signal measurement unit preferably measures the intensity of the periodic signal extracted from the differential signal by the second extraction unit.

  In this way, it is possible to measure the signal intensity with high sensitivity by extracting the periodic component synchronized with the intensity modulation from the reflected wave and measuring it, so that the output is small compared with the configuration without the intensity modulation. The crystallinity can be evaluated with the same degree of accuracy even if the pumping light radiating part is used, whereby the pumping light radiating part can be miniaturized. On the other hand, crystallinity can be evaluated with higher accuracy when using an excitation light emitting section having the same level of output as compared with the configuration without intensity modulation.

  As described above, according to the present invention, the method for evaluating the crystallinity of a semiconductor thin film capable of evaluating the crystallinity of a semiconductor thin film formed on the substrate with high sensitivity while easily arranging the substrate on the sample stage, and A crystallinity evaluation apparatus can be provided.

It is the schematic which shows the whole structure of the crystallinity evaluation apparatus of the semiconductor thin film which concerns on 1st Embodiment. It is the schematic which shows the whole structure of the crystallinity evaluation apparatus of the semiconductor thin film which concerns on 2nd Embodiment. It is the schematic which shows the whole structure of the crystallinity evaluation apparatus of the semiconductor thin film which concerns on 3rd Embodiment.

  Hereinafter, a first embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic diagram showing the overall configuration of a semiconductor thin film crystallinity evaluation apparatus (hereinafter also simply referred to as “evaluation apparatus”) 10 according to the present embodiment.

  The evaluation apparatus 10 is used in a production line for a polycrystalline silicon semiconductor thin film (hereinafter referred to as “p-Si semiconductor thin film”) 12, and is formed on a glass substrate (base material) 11 and the glass substrate 11. This is for evaluating the crystallinity of the p-Si semiconductor thin film 12 of the sample 13 having the p-Si semiconductor thin film 12 formed thereon. As the glass substrate 11 according to the present embodiment, for example, a glass substrate having a length of 730 mm, a width of 920 mm, and a thickness of 0.5 mm is used. The p-Si semiconductor thin film 12 formed on the glass substrate 11 has a thickness of about 50 nm, a refractive index of 5.4, and an extinction coefficient of 0.329 (λ = 350 nm), for example.

  The evaluation apparatus 10 according to this embodiment includes a stage (sample stage) 14 for placing the sample 13 and excitation light irradiation for irradiating the sample 13 placed (arranged) on the stage 14 with excitation light. Means 15, microwave irradiating means 20 for irradiating the sample 13 with microwaves, microwave measuring means 30 for measuring the intensity of the reflected wave of the microwave from the sample 13, and controlling each part of the evaluation apparatus 10 etc. And a computer 50 for outputting an evaluation result from the computer 50 to the outside. In the present embodiment, a part of the computer 50 (specifically, the control unit 51) constitutes a part of the microwave irradiation means 20.

  The stage 14 has a placement surface (arrangement surface) 14a, and the sample 13 is placed on the placement surface 14a. The stage 14 is made of a conductor. Specifically, the stage 14 is a metal plate on which the sample 13 can be placed so that the glass substrate 11 is in direct contact with the placement surface 14a with the surface of the p-Si semiconductor thin film 12 facing upward. It is. The stage 14 of the present embodiment is composed of an aluminum plate. The stage 14 extends along the surface of the p-Si semiconductor thin film 12 in the x-axis direction (the direction from the front to the back in FIG. 1) and the y-axis direction orthogonal to the x-axis (the right side in FIG. 1). And is driven in each axial direction by driving means (not shown) based on a command signal from the stage controller 16 controlled by the computer 50.

  The driving means of the present embodiment drives only the stage 14, but is not limited to this. That is, the drive means moves the excitation light irradiation means 15 and the microwave irradiation means 20 and the stage 14 relative to each other so that the surface of the p-Si semiconductor thin film 12 can be scanned over the entire area with excitation light and microwaves. It suffices to be configured.

  The excitation light irradiating means 15 irradiates the surface of the p-Si semiconductor thin film 12 with excitation light in order to excite carriers. The excitation light irradiation means 15 of this embodiment includes an excitation light source 15a and a mirror 15b that reflects the excitation light emitted from the excitation light source 15a to the sample 13 side. The excitation light source 15a emits ultraviolet light. This ultraviolet light uses the ultraviolet light obtained as the third harmonic of the YLF laser. Specifically, the excitation light source 15a emits ultraviolet pulse excitation light having an oscillation wavelength of 349 nm, a pulse width of 10 ns, and a pulse energy of 10 uJ / pulse. The emitted light from the excitation light source 15a is applied to the p-Si semiconductor thin film 12 with a spot diameter of φ1.5 mm. At the wavelength of the excitation light (349 nm), the penetration length of the excitation light with respect to the p-Si semiconductor thin film 12 is about 10 nm, which is sufficiently small as compared with the film thickness of 50 nm of the p-Si semiconductor thin film 12. Carriers are often generated.

  The microwave irradiation means 20 includes a transmission wavelength variable microwave oscillator (microwave radiation unit) 21, an amplifier (wavelength adjustment unit) 22 that amplifies the microwave, a control unit 51 that controls the microwave oscillator 21, and an amplifier The directional coupler 23 for dividing the microwave from 22 into the microwaves O1 and O2, the magic T24 for dividing the microwave O1 into two, and the magic T24 and the stage 14 are provided. The first waveguide 25 and the second waveguide 26 are provided.

  The microwave oscillator 21 outputs (emits) a microwave that is an electromagnetic wave. The microwave oscillator 21 is connected to the control unit 51 and adjusts the wavelength of the microwave to be output (transmitted) based on the instruction signal C1 from the control unit 51. The microwave oscillator 21 of the present embodiment is configured to output a microwave having a wavelength of 4.7 mm (frequency is 64 GHz), for example, and to change the wavelength.

  The amplifier 22 is disposed between the microwave oscillator 21 and the directional coupler 23 and amplifies the microwave output from the microwave oscillator 21.

  The control part 51 is arrange | positioned in the computer 50, and is provided with the 1st instruction | indication part 51a, the 1st memory | storage part 51b, and the 2nd instruction | indication part 51c. Before the crystallinity evaluation of the p-Si semiconductor thin film 12, the first instruction unit 51a changes the wavelength of the microwave output from the microwave oscillator 21 within a predetermined range with respect to the microwave oscillator 21. It is a part to instruct. Thereby, in the said evaluation apparatus 10, a microwave is irradiated with changing the frequency within the said predetermined range with respect to the p-Si semiconductor thin film 12 before crystallinity evaluation, and the reflected wave is measured.

  The first storage unit 51b is a part to which the first instruction unit 51a and the microwave measurement unit 30 are connected, and stores the information received from the first instruction unit 51a and the microwave measurement unit 30 in association with each other. is there. Specifically, the first storage unit 51b has the wavelength of the microwave when the p-Si semiconductor thin film 12 is irradiated with the microwave while changing the wavelength, and the reflection measured by the microwave measuring unit 30 at that time. Stores the relationship with the signal strength of the wave. The signal intensity R2 of the reflected wave is the magnitude of intensity change caused by the excitation light of the reflected wave from the p-Si semiconductor thin film 12.

  The second instruction unit 51c outputs a microwave having a specific wavelength based on the relationship between the wavelength of the microwave stored in the first storage unit 51b and the signal intensity R2 of the reflected wave in the microwave. Thus, the instruction signal C1 is output to the microwave oscillator 21. Specifically, the second instruction unit 51c performs irradiation to evaluate the crystallinity of the p-Si semiconductor thin film 12 based on the relationship between the microwave stored in the first storage unit 51b and the signal intensity R2. Determine the wavelength (specific wavelength) of the microwave to be played. Specifically, the second indicator 51c irradiates the p-Si semiconductor thin film 12 with the microwave at that wavelength, and measures the reflected wave to set a specific wavelength so that a large signal intensity can be obtained. decide. As the specific wavelength of the present embodiment, the largest signal intensity R2 among the signal intensity R2 stored in the first storage unit 51b is obtained by changing the wavelength in the predetermined range (changing the frequency in the predetermined range). The wavelength λ or the wavelength approximated thereto, and the wavelength approximated to the extent that a signal intensity of 90% or more is obtained with respect to the largest signal intensity R2.

  Here, λ from which the largest signal strength R2 is obtained will be described.

  In order to maximize the signal intensity R2, the standing wave formed by the interference between the microwave irradiated to the p-Si semiconductor thin film 12 and the microwave reflected by the mounting surface 14a has the highest amplitude. It is necessary to be influenced by the characteristic change accompanying the irradiation of the excitation light at the measurement site (surface) of the p-Si semiconductor thin film 12 at a position (antinode) with a large diameter.

Such λ is defined as a distance from the surface of the p-Si semiconductor thin film 12 to the mounting surface 14a of the stage 14 being d.
d = λ / 4n + N (λ / 2n) (1)
The relationship holds. Here, n is the refractive index of the glass substrate, and N is 0 or any positive integer. By transforming this equation (1),
λ = [4n / (1 + 2N)] d (2)
It becomes.

  And the 2nd instruction | indication part 51c outputs the instruction | indication signal C1 to the microwave oscillator 21 so that the wavelength of the output microwave may be changed into a specific wavelength.

  The control unit 51 as described above changes the wavelength of the microwave output from the microwave oscillator 21 between 4.6 and 6.7 mm (microwave between 65 and 45 GHz). It should be noted that the variable range of the wavelength of the microwave needs to be set in a range including λ in the formula (2), and the value of λ varies depending on the thickness of the glass substrate 11 used in the sample 13. Therefore, in the crystallinity evaluation of the p-Si semiconductor thin film 12, when the glass substrate 11 having a thickness different from that of the present embodiment is used, the wavelength of the microwave can be changed based on the thickness of the glass substrate 11 used. The range is changed.

  The directional coupler 23 is for adjusting the course of the microwave. The directional coupler 23 of the present embodiment is configured to branch the microwave that has reached from the microwave oscillator 21 through the amplifier 22 into two.

  The magic T24 bifurcates the microwave O1 from the directional coupler 23 into microwaves O3 and O4 and outputs a differential signal R1 of the reflected waves from the sample 13 of the microwaves O3 and O4. is there.

  The first waveguide 25 is a member that guides microwaves. Specifically, the first waveguide 25 guides the microwave O3 from the magic T24 to the irradiation range of the excitation light in the surface of the p-Si semiconductor thin film 12, and the microwave O3 from the irradiation range. It is configured to guide the reflected wave to the magic T24. In other words, in addition to the function as an antenna (waveguide antenna) that radiates the microwave O3, the first waveguide 25 captures the reflected wave of the microwave O3 from the excitation light irradiation range at the tip opening. And has a function of guiding to Magic T24.

  The second waveguide 26 is a member that guides microwaves. Specifically, the second waveguide 26 guides the microwave O4 from the magic T24 to a range (near the irradiation range) in the surface of the p-Si semiconductor thin film 12 where the excitation light is not irradiated, The reflected wave of the microwave O4 from this range is configured to be guided to the magic T24. In other words, in addition to the function as an antenna (waveguide antenna) that radiates the microwave O4, the second waveguide 26 captures the reflected wave of the p-Si semiconductor thin film 12 at the opening at the tip thereof, and reaches the magic T24. Has a function to guide. The second waveguide 26 is configured such that the path length for guiding the microwaves is equal to that of the first waveguide 25.

  Note that, as described above, the first waveguide 25 and the second waveguide 26 have a function of capturing the reflected waves of the microwaves O3 and O4 at the tip opening and guiding them to the magic T24. Has a function of outputting the differential signal R1 of the reflected wave, the first waveguide 25, the second waveguide 26, and the magic T24 also constitute a part of the microwave measuring means 30.

  The microwave measuring means 30 includes the first waveguide 25 and the second waveguide 26, a differential signal deriving unit 31, and a signal processing unit (differential signal) to which the differential signal deriving unit 31 is connected. A measurement unit) 32. The differential signal deriving unit 31 includes a magic T24 that outputs the differential signal R1 and a mixer 33 that guides the microwave O2.

  The mixer 33 receives the differential signal R1 of the reflected waves of the microwaves O3 and O4 from the magic T24, and outputs the detection signal S1 by mixing the differential signal R1 and the microwave O2 from the microwave oscillator 21. To do. The detection signal S1 is a signal representing the intensity of the differential signal R1, and is input to the signal processing unit 32. Thus, since the mixer 33 is for detecting the intensity of the differential signal R1, instead of the mixer 33, the differential signal R1 is input and an electric signal (signal intensity R2) corresponding to the intensity is input. A microwave detector (detector) may be provided.

  The signal processing unit 32 is a part that measures the intensity of the differential signal R1 based on the detection signal S1 input from the mixer 33. The measurement result in the signal processing unit 32 is output to the computer 50 as the signal intensity R2.

  The computer 50 includes a second storage unit 52 and an evaluation unit 53 in addition to the control unit 51 (the first and second instruction units 51a and 51c and the first storage unit 51b). Control of each part that constitutes is performed. The second storage unit 52 is a part that stores the signal intensity R2 from the signal processing unit 32 and signals sent from each part constituting the evaluation apparatus 10 so as to be freely put in and out. The evaluation unit 53 is a part that evaluates the crystallinity of the p-Si semiconductor thin film 12 at each position based on the signal intensity R2 received from the signal processing unit 32. Specifically, crystallinity is evaluated by deriving the time (lifetime) until carriers excited by irradiation of excitation light to the p-Si semiconductor thin film 12 are recombined based on the signal intensity R2. . The result evaluated by the evaluation unit 53 is output to the output means 60 as an evaluation signal.

  The output means 60 outputs the evaluation of crystallinity of each part of the p-Si semiconductor thin film 12 evaluated by the evaluation unit 53. The output means 60 of the present embodiment displays the evaluation result on the screen and outputs the evaluation result to the manufacturing line in order to feed back the evaluation result to the manufacturing conditions.

  A method for evaluating the crystallinity of the p-Si semiconductor thin film 12 using the evaluation apparatus 10 configured as described above will be described.

  First, a sample 13 formed by forming a p-Si semiconductor thin film 12 on a glass substrate 11 is placed on a stage 14. Specifically, the sample 13 is placed on the stage 14 such that the surface opposite to the surface on which the p-Si semiconductor thin film 12 is formed is in contact with the placement surface 14 a of the stage 14. That is, the sample 13 is placed on the stage 14 so that the glass substrate 11 and the placement surface 14a of the stage 14 are in direct contact.

  Next, the excitation light is irradiated from the excitation light irradiation means 15 to a specific position (measurement site) on the surface of the p-Si semiconductor thin film 12, and the excitation light is irradiated on the surface of the p-Si semiconductor thin film 12. The microwave is irradiated to the range through the first waveguide 25, while the microwave is irradiated to the range not irradiated with the excitation light through the second waveguide 26. Then, before the evaluation of the crystallinity of the p-Si semiconductor thin film 12 by the evaluation apparatus 10, the microwave oscillator 21 generates a microwave signal based on the instruction signal C <b> 1 from the control unit 51 (first instruction unit 51 a). The wavelength is changed within the predetermined range.

  The differential signals R1 of the reflected waves O3 and O4 that have passed through the waveguides 25 and 26 are output from the magic T24 to the mixer 33, and the detection signal S1 is mixed based on the differential signal R1 and the microwave O2. 33 to the signal processing unit 32. Based on the detection signal S1 input to the signal processing unit 32, the signal processing unit 32 measures the intensity and the intensity change caused by the excitation light, and the signal intensity R2 is transmitted to the computer 50. Specifically, based on the detection signal S <b> 1 input to the signal processing unit 32, the signal processing unit 32 determines the excitation light in the intensity of the reflected wave from the p-Si semiconductor thin film 12 that changes due to the irradiation of the excitation light. A periodic component synchronized with the intensity modulation is extracted (detected), and the detected signal is output to the computer 50 as the signal intensity R2.

  At this time, the wavelength of the microwave changed by the amplifier 22 and the signal intensity R2 measured by the microwave measuring unit 30 at each wavelength are stored in the first storage unit 51b in an associated state. The

  Next, when the microwave wavelength and the signal intensity R2 of the reflected wave are stored in the first storage unit 51b as described above, the second instruction unit of the control unit 51 is based on this. 51c outputs an instruction signal C1 to the microwave oscillator 21, and changes the wavelength of the microwave output by the microwave oscillator 21 to a specific wavelength based on the instruction signal C1. This specific wavelength is the wavelength λ at which the highest signal intensity R2 is obtained from the signal intensity R2 stored in the first storage unit 51b as described above, or a wavelength close to this wavelength λ. The wavelength approximates to such an extent that a signal intensity R2 of 90% or more is obtained with respect to the intensity R2.

  The microwave of this specific wavelength is irradiated to the p-Si semiconductor thin film 12, and this reflected wave enters each of the waveguides 25 and 26. Similarly to the above, the differential signal R1 of the reflected waves O3 and O4 passing through the waveguides 25 and 26 is output from the magic T24 to the mixer 33, and based on the differential signal R1 and the microwave O2. The detection signal S1 is output from the mixer 33 to the signal processing unit 32, and the signal strength R2 is transmitted from the signal processing unit 32 to the evaluation unit 53 of the computer 50. The evaluation unit 53 that has received the signal intensity R2 evaluates the crystallinity at the measurement site irradiated with the microwave. The evaluation result and the position information of the measurement site in the p-Si semiconductor thin film 12 are associated in the computer 50 and stored in the second storage unit 52.

  Then, the stage 14 is driven by the driving means, the p-Si semiconductor thin film 12 moves in the respective xy axial directions, and other portions are measured by irradiation with microwaves having specific wavelengths in the same manner as described above. The result (signal intensity R2) is evaluated by the evaluation unit 53, and the signal intensity R2 is associated with the acquired positional information of the p-Si semiconductor thin film 12 and stored in the second storage unit 52. By repeating this, evaluation results of crystallinity at a plurality of positions in one sample 13, that is, one p-Si semiconductor thin film 12, are obtained.

  These results are fed back to the production conditions in the production line of the p-Si semiconductor thin film 12 to be evaluated by the output means 60 and displayed on the screen.

  According to the evaluation apparatus 10 described above, the sample 13 is directly placed on the placement surface 14a of the stage 14 (specifically, placed so that the glass substrate 11 is in contact), so that dust or the like enters during the placement. It is only necessary to pay attention to between the glass substrate 11 and the mounting surface 14a, and the stage 14 is compared with a conventional case where a dielectric is interposed between the glass substrate 11 and the stage 14. The sample 13 (glass substrate 11) can be easily placed on the substrate.

  Moreover, 4n / (1 + 2N) times (n: glass) the distance from the surface of the p-Si semiconductor thin film 12 to the mounting surface 14a of the stage 14 on which the glass substrate 11 on which the p-Si semiconductor thin film 12 is formed is disposed. Reflection from the p-Si semiconductor thin film 12 by irradiating the p-Si semiconductor thin film 12 with a wavelength λ of the refractive index of the substrate 11, N: 0 or any positive integer), or a wavelength close thereto. Even if the intensity of the wave is weak, the crystallinity can be evaluated with high sensitivity (that is, high S / N).

  That is, the standing wave formed by the interference between the microwave irradiated to the p-Si semiconductor thin film 12 and the microwave reflected by the mounting surface 14a is p- at the position (antinode) having the largest amplitude. By receiving the influence of the characteristic change accompanying the irradiation of the excitation light at the measurement site (surface) of the Si semiconductor thin film 12, the intensity change (signal intensity R2) due to the excitation light irradiation in the reflected wave of the microwave becomes the largest. If such a large signal intensity R2 is obtained, the crystallinity can be evaluated with high sensitivity even if the intensity of the reflected wave is weak. Therefore, in order to obtain a signal intensity R2 sufficient for evaluating crystallinity, the wavelength λ at which the largest signal intensity R2 is obtained or a signal intensity R2 that is 90% or more of the largest signal intensity R2 is obtained. By irradiating the p-Si semiconductor thin film 12 with a microwave having a wavelength approximate to the wavelength λ, it is possible to perform sufficient crystallinity evaluation in a short time.

  Furthermore, by outputting the evaluation result of the p-Si semiconductor thin film 12 by the output means 60, the evaluation result can be quickly fed back to the manufacturing conditions in the production line of the p-Si semiconductor thin film 12.

  Moreover, in the said embodiment, on the p-Si semiconductor thin film 12, the reflected wave in the site | part in which the carrier was produced | generated by irradiation of excitation light and the reflectance of the microwave increased, and the said reflectance which is not irradiated with excitation light The intensity of the weak reflected wave from the p-Si semiconductor thin film 12 is measured by measuring the detection signal S1 (intensity of the differential signal R1) derived from both the reflected wave and the reflected wave at the part where the frequency does not change. The fluctuation can be measured with higher sensitivity, and the crystallinity can be evaluated with higher accuracy as a result.

  Moreover, in the said embodiment, it becomes possible to evaluate the crystallinity in each position on the said p-Si semiconductor thin film 12 because the stage 14 is comprised so that a movement is possible.

  Next, a second embodiment of the present invention will be described with reference to FIG. 2, but the same reference numerals are used for the same components as those of the first embodiment, and a detailed description is omitted, and only the different components are described in detail. Explained.

  The evaluation apparatus 110 according to the present embodiment includes a stage 14, an excitation light irradiation unit 150, a microwave irradiation unit 20, a microwave measurement unit 130, a measurement light irradiation unit 40, a measurement light measurement unit 45, and a computer. 50 and output means 60.

  The excitation light irradiation unit 150 includes an excitation light source (excitation light emitting unit) 151 and a modulation unit 152 that modulates the intensity of the excitation light emitted from the excitation light source 151 at a predetermined period. A semiconductor laser is used for the excitation light source 151 of the present embodiment. This semiconductor laser has a wavelength of 405 nm, a maximum output of 600 mW, and a size including a head cooling module of about 30 × 30 × 30. That is, this semiconductor laser is usually smaller than a YLF pulse laser having a size including a cooling module of about W100 mm × L200 mm × H100 mm. The modulation unit 152 includes an excitation light source driving circuit 153 for controlling the excitation light source 151 and a waveform generator 154 that supplies a waveform to the excitation light source driving circuit 153 so that the waveform of the excitation light becomes a rectangular wave. The modulation unit 152 performs intensity modulation so that the waveform of the excitation light becomes a rectangular wave.

  The microwave measuring unit 130 includes a first waveguide 25 and a second waveguide 26, a differential signal deriving unit 31, and a pumping light of the modulation unit 152 from a detection signal from the differential signal deriving unit 31. A lock-in amplifier (extraction unit) 131 that extracts a periodic component synchronized with intensity modulation and outputs it as a periodic signal S2, and a differential signal measurement unit 132 that measures the intensity of the periodic signal S2 from the lock-in amplifier 131. Prepare. The differential signal measurement unit 132 according to the present embodiment is disposed inside the computer 50.

  In the evaluation apparatus 110 configured as described above, when the crystallinity of the p-Si semiconductor thin film 12 is evaluated, the detection signal S1 is output from the mixer 33 based on the differential signal R1 from the magic T24 and the microwave O2. It is output to the lock-in amplifier 131. In the lock-in amplifier 131, a periodic component synchronized with the intensity modulation of the excitation light in the modulation unit 152 is extracted from the detection signal S1, and this periodic component is output to the differential signal measurement unit 132 as the periodic signal S2. Then, the intensity of the periodic signal S2 input to the differential signal measuring unit 132 is measured and output to the evaluation unit 53 as the signal intensity R2.

  As described above, with the configuration in which the excitation light is intensity-modulated at a predetermined period, the signal intensity R2 can be measured with high sensitivity, and the excitation light source 151 can be downsized. That is, the periodic component synchronized with the intensity modulation is extracted from the reflected wave by the lock-in amplifier 131, and the intensity is measured by the differential signal measuring unit 132, whereby the intensity of the weak reflected wave from the p-Si semiconductor thin film 12 is measured. Can be measured with high sensitivity. Therefore, crystallinity can be evaluated with the same degree of accuracy even when a small excitation light source 151 having a small output is used as compared with a configuration in which excitation light is irradiated without intensity modulation.

  Since the excitation light source 151 can be downsized in this way, the degree of freedom of installation of the evaluation device 110 on the production line is improved. In addition, the sensor head on which the excitation light irradiation unit 150 and the microwave irradiation unit 20 are mounted can be downsized, and the crystallinity of the large p-Si semiconductor thin film 12 can be evaluated. Specifically, in the present embodiment, the entire region of the p-Si semiconductor thin film 12 is scanned by driving the stage 14. However, since the stage 14 increases as the p-Si semiconductor thin film 12 increases in size, It becomes difficult to drive on the production line. Therefore, by reducing the size of the excitation light irradiating means 150, the sensor head can be reduced in size, and the sensor head can be driven to scan the entire area of the large p-Si semiconductor thin film 12. The crystallinity of the large p-Si semiconductor thin film 12 can be evaluated.

  In addition, since the crystallinity can be evaluated with the same degree of accuracy as compared with the case where the intensity of the excitation light is not modulated even if the excitation light source 151 is downsized, it is directly applied to the mounting surface 14a of the stage 14 as in the first embodiment. Even when the sample 13 is placed, a sufficient signal intensity R2 can be obtained. As a result, attention must be paid to the entry of dust and the like between the glass substrate 11 and the placement surface 14a. As compared with the conventional case where a dielectric is interposed between the glass substrate 11 and the stage 14, the sample 13 (glass substrate 11) can be easily placed on the stage 14.

  On the other hand, the crystallinity of the p-Si semiconductor thin film can be evaluated with higher accuracy when the excitation light source 151 having the same output is used as compared with the case where the intensity of the excitation light is not modulated.

  Even when the excitation light is irradiated with intensity modulation, the surface from the surface of the p-Si semiconductor thin film 12 to the mounting surface 14a of the stage 14 on which the glass substrate 11 on which the p-Si semiconductor thin film 12 is formed is disposed. Irradiation to the p-Si semiconductor thin film 12 with a wavelength λ of 4n / (1 + 2N) times the distance (n: refractive index of the glass substrate 11, N: 0 or any positive integer) or a wavelength close thereto. Thus, even if the intensity of the reflected wave from the p-Si semiconductor thin film 12 is weak, the crystallinity can be evaluated with high sensitivity (that is, high S / N).

  Next, a third embodiment of the present invention will be described with reference to FIG. 3, but the same reference numerals are used for the same components as those in the first and second embodiments, and detailed descriptions are omitted, and different configurations are described. Only the details will be described.

  The evaluation apparatus 210 according to the present embodiment includes a stage 14, excitation light irradiation means 15, microwave irradiation means 220, microwave measurement means 230, computer 50, and output means 60.

  The excitation light irradiation means 15 of this embodiment irradiates the surface of the p-Si semiconductor thin film 12 directly with excitation light without using a mirror or the like.

  The microwave irradiation means 220 includes a microwave oscillator 21, an amplifier 22, a directional coupler 23 for adjusting the course of the microwave from the amplifier 22, and between the amplifier 22 and the directional coupler 23. A third waveguide 225 provided and a fourth waveguide 226 provided between the directional coupler 23 and the stage 14 are provided. As in the first embodiment, the control unit 51 of the computer 50 also constitutes a part of the microwave irradiation means 120.

  The wavelength of the microwave output from the microwave oscillator 21 is adjusted (changed) by the microwave oscillator 21 that has received the instruction signal C <b> 1 from the first instruction unit 51 a, and is directed through the third waveguide 225. It reaches the coupler 23 and is guided to the fourth waveguide 226 by the directional coupler 23. The microwave is guided to the surface of the p-Si semiconductor thin film 12 of the sample 13 on the stage 14 through the fourth waveguide 226. Specifically, the microwave is guided to a range irradiated with excitation light on the surface of the p-Si semiconductor thin film 12. The microwave reflected by the sample 13 is guided to the directional coupler 23 through the fourth waveguide 226, and is guided to the microwave detector 132 by the directional coupler 23. The microwave detector 132 receives the reflected microwave and outputs the intensity change to the computer 50 as a signal intensity R2.

  As described above, the fourth waveguide 226 has a function of capturing the reflected wave of the microwave at the tip opening and guiding it to the directional coupler 23. The directional coupler 23 detects the reflected wave by the microwave detection. The fourth waveguide 226 and the directional coupler 23 also constitute a part of the microwave measuring means 230 since it has a function of guiding to the instrument 232 side.

  This microwave measurement means 230 includes a microwave detector 232 that measures the intensity of the reflected wave, a directional coupler 23, and a microwave detector 232 in addition to the fourth waveguide 126 and the directional coupler 23. And a fifth waveguide 227 provided therebetween. The microwave detector 232 measures the intensity of the reflected wave of the microwave that has reached through the fifth waveguide 227 from the directional coupler 23 and outputs the measured value to the computer 50 as the signal intensity R2.

  A method for evaluating the crystallinity of the p-Si semiconductor thin film 12 using the evaluation apparatus 210 configured as described above will be described.

  The excitation light irradiating means 15 irradiates the surface of the p-Si semiconductor thin film 12 of the sample 4 with excitation light, and the microwave irradiating means 220 to the range of the p-Si semiconductor thin film 12 including the range irradiated with the excitation light. Irradiate waves. At this time, the microwave oscillator 21 changes the wavelength of the microwave within a predetermined range in accordance with an instruction from the first instruction unit 51a, and the changed wavelength of the microwave and the signal intensity R2 measured at each wavelength. Are stored in the first storage unit 51b.

  Based on the information stored in the first storage unit 51b (specifically, information in which the wavelength of the microwave and the signal intensity R2 of the reflected wave are related), the second instruction unit 51c outputs the output micro signal. An instruction signal C1 is output to the microwave oscillator 21 so as to change the wavelength of the wave to a specific wavelength. In response to the instruction signal C1, the microwave oscillator 21 changes the wavelength of the output microwave to a specific wavelength.

  Then, the reflected wave from the surface of the p-Si semiconductor thin film 12 is guided to the microwave detector 232 of the microwave measuring means 130, and the intensity change due to the intensity and excitation light is measured by the microwave detector 232. The signal strength R2 is transmitted to the evaluation unit 53 of the computer 50. The evaluation unit 53 that has received the signal intensity R2 evaluates the crystallinity of the measurement site irradiated with the microwave, associates the evaluation result with the position information of the measurement site in the p-Si semiconductor thin film 12, and Stored in the second storage unit 52.

  Then, the stage 14 is driven by the driving means, and the measurement at each position of the p-Si semiconductor thin film 12 is repeated, thereby obtaining crystallinity evaluation results at a plurality of positions of one p-Si semiconductor thin film 12. It is done.

  These results are fed back to the production conditions in the production line of the p-Si semiconductor thin film 12 to be evaluated by the output means 60 and displayed on the screen.

  As described above, even when the microwave is applied to the p-Si semiconductor thin film 12 without branching, the sample 13 is directly placed on the placement surface 14a of the stage 14 so that the microwave can be placed. When it is necessary to pay attention to dust and the like only between the glass substrate 11 and the mounting surface 14a, a dielectric is interposed between the glass substrate 11 and the stage 14 as in the prior art. As compared with the case, the sample 13 (glass substrate 11) can be easily placed on the stage 14. Moreover, 4n / (1 + 2N) times (n: glass) the distance from the surface of the p-Si semiconductor thin film 12 to the mounting surface 14a of the stage 14 on which the glass substrate 11 on which the p-Si semiconductor thin film 12 is formed is disposed. By irradiating the p-Si semiconductor thin film 12 with a microwave having a wavelength λ of the refractive index of the substrate 11, N: 0 or any positive integer), or a wavelength similar thereto, the wavelength from the p-Si semiconductor thin film 12 is increased. Even if the intensity of the reflected wave is weak, the crystallinity can be evaluated with high sensitivity (that is, high S / N).

  The crystallinity evaluation method and crystallinity evaluation apparatus for a semiconductor thin film according to the present invention are not limited to the above-described embodiments, and various changes can be made without departing from the scope of the present invention. .

  For example, in the first and second embodiments, after the wavelength of the microwave irradiated to the p-Si semiconductor thin film 12 is once changed within the predetermined range, the microwave is changed to the specific wavelength. However, for example, in the production line, if the thickness of the sample 13 to be produced, that is, the glass substrate 11 and the p-Si semiconductor thin film 12 is substantially constant (if the thickness variation is small), the microwave is generated from the beginning. The p-Si semiconductor thin film 12 may be irradiated with the specific wavelength, and measurement (evaluation) of the p-Si semiconductor thin film 12 may be performed.

  In the first and second embodiments, the microwave wavelength and the signal intensity R2 of the reflected wave in the microwave are applied by irradiating the p-Si semiconductor thin film 12 with the microwave while changing the wavelength within the predetermined range. Is obtained, and the wavelength of the microwave actually irradiated to the p-Si semiconductor thin film 12 is determined based on this information. However, the present invention is not limited to this. For example, based on the acquired information, 4n / (1 + 2N) times the distance from the surface of the p-Si semiconductor thin film 12 to the placement surface 14a of the stage 14 on which the sample 13 is placed (n: refraction of the glass substrate 11) Ratio, N: 0 or any positive integer) may be obtained, and the wavelength of the microwave actually irradiated may be determined based on this wavelength λ.

  Also in the third embodiment, a so-called modulation excitation method in which excitation light is intensity-modulated at a predetermined period as in the second embodiment may be used.

10 Evaluation apparatus 11 Glass substrate (base material)
12 p-Si semiconductor thin film (semiconductor thin film)
14 stage (sample stage)
14a Placement surface (placement surface)
15 Excitation light irradiation means 20 Microwave irradiation means 21 Microwave oscillator (light source)
22 Amplifier (wavelength adjustment unit)
30 Microwave Measurement Unit 51 Control Unit 51a First Storage Unit 51b Instruction Unit 53 Evaluation Unit (Evaluation Unit)
60 Output means R2 Signal intensity λ Wavelength

Claims (6)

A method for evaluating the crystallinity of a semiconductor thin film formed on a substrate,
An arrangement step of arranging the base material on the arrangement surface of the sample stage so that the surface opposite to the surface on which the semiconductor thin film is formed,
An excitation light irradiation step of irradiating excitation light for exciting carriers to the semiconductor thin film on the substrate placed on the sample stage;
A microwave irradiation step of irradiating a microwave having a specific wavelength to a range of the semiconductor thin film including a range irradiated with the excitation light in the excitation light irradiation step;
A measurement step of measuring the intensity of the reflected wave of the microwave from the semiconductor thin film;
By irradiating the semiconductor thin film with the microwave while changing the wavelength in a predetermined range in advance before performing the microwave irradiation step, the relationship between the wavelength of the microwave and the signal intensity of the reflected wave in the microwave An acquisition process for acquiring information ,
In the microwave irradiation step, the wavelength of the microwave to be actually irradiated is determined based on the information in the acquisition step,
The microwave irradiated in the microwave irradiation step is 4n / (1 + 2N) times (n) the distance from the surface of the semiconductor thin film to the arrangement surface of the sample table on which the substrate on which the semiconductor thin film is formed is arranged. : refractive index of the substrate, N: wavelength of 0 or any positive integer) lambda, or, the microwave having a wavelength of the approximate a wavelength approximating to the wavelength lambda when irradiating the semiconductor thin film Indeed the magnitude of the signal intensity of the intensity change due to the excitation light of the resulting reflected wave is to signal strength that obtained when the microwaves with the wavelength λ is irradiated on the semiconductor thin film 9 0 crystalline method for evaluating a semiconductor thin film characterized by having a wavelength which approximates to the wavelength λ to the extent that a higher%. In the crystallinity evaluation method of the semiconductor thin film of Claim 1 ,
In the microwave irradiation step, the measurement microwave is irradiated to each of the excitation light irradiation range and the excitation light irradiation range,
The measuring step includes a differential signal deriving step for deriving a differential signal obtained by subtracting a reflected wave from outside the irradiation range from a reflected wave from the irradiation range, and a differential signal derived in the differential signal deriving step. And a differential signal measuring step for measuring the intensity of the semiconductor thin film. An apparatus for evaluating the crystallinity of a semiconductor thin film formed on a substrate,
A sample stage having an arrangement surface, on which the substrate is arranged;
Excitation light irradiation means for irradiating excitation light for exciting carriers to a semiconductor thin film on a substrate disposed on the sample stage;
A microwave irradiation means for irradiating a range of the semiconductor thin film including a range irradiated with the excitation light with a microwave;
Microwave measuring means for measuring the intensity of the reflected wave of the microwave from the semiconductor thin film;
Evaluation means for evaluating the crystallinity of the semiconductor thin film based on the measurement value of the microwave measurement means;
Output means for outputting an evaluation of the crystallinity of the semiconductor thin film evaluated by the evaluation means,
The microwave irradiating means includes a microwave radiating unit that radiates microwaves, a wavelength adjusting unit that changes the wavelength of the microwave radiated from the microwave radiating unit, and a control unit that controls the wavelength adjusting unit. Have
The control unit is configured to cause the microwave adjusting unit to emit a microwave while changing the wavelength by the wavelength adjusting unit, the wavelength of the microwave obtained by the radiation, and the semiconductor in the microwave. A storage unit that stores a relationship with a signal intensity that is a magnitude of an intensity change caused by excitation light of a reflected wave from a thin film; a wavelength of the microwave stored in the storage unit; and a signal intensity of the reflected wave And a second indicating unit that causes the microwave radiating unit to emit a microwave having a predetermined wavelength based on the relationship. In the crystallinity evaluation apparatus of the semiconductor thin film of Claim 3 ,
The excitation light irradiating means includes an excitation light emitting unit that emits the excitation light, and a modulation unit that modulates the intensity of the excitation light emitted from the excitation light emitting unit at a predetermined period,
The microwave measurement means includes a first extraction unit that extracts a periodic component synchronized with the intensity modulation of excitation light in the modulation unit from the reflected wave of the microwave from the semiconductor thin film, and the first extraction unit And a periodic signal measuring unit for measuring the intensity of the periodic signal extracted in (1). In the crystallinity evaluation apparatus of the semiconductor thin film of Claim 3 ,
The microwave irradiating means is configured to irradiate the microwave to the excitation light irradiation range and the excitation light irradiation range, respectively, of the semiconductor thin film,
The microwave measuring means derives a differential signal by deriving a differential signal obtained by subtracting a reflected wave of the microwave from outside the irradiation range from a reflected wave of the microwave from the irradiation range, and the differential signal derivation And a differential signal measuring unit for measuring the intensity of the differential signal derived by the unit. The crystallinity evaluation apparatus for a semiconductor thin film according to claim 5 ,
The excitation light irradiating means includes an excitation light emitting unit that emits the excitation light, and a modulation unit that modulates the intensity of the excitation light emitted from the excitation light emitting unit at a predetermined period,
The microwave irradiation means further includes a second extraction unit that extracts a periodic component synchronized with the intensity modulation of the excitation light in the modulation unit from the differential signal derived by the differential signal deriving unit,
The apparatus for evaluating crystallinity of a semiconductor thin film, wherein the differential signal measuring unit measures the intensity of a periodic signal extracted from the differential signal by the second extracting unit.

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