JP3983762B2 - X-ray diffraction measurement analysis method and program - Google Patents

Description

  The present invention relates to an X-ray diffraction measurement analysis method and program, and more particularly to an X-ray diffraction measurement analysis method and program suitable for measurement and analysis of a superlattice structure in which different types of thin films are alternately stacked.

  A crystal structure having a superlattice structure in which different types of thin films are alternately stacked is applied to many applications, using an active layer of a high-power semiconductor laser used in the communication field as a representative example.

  Recently, the accuracy required for thin film production has become more stringent than before, and high-precision measurement analysis methods using X-ray diffraction have been widely used when measuring and analyzing thin films. The so-called rocking curve measurement / analysis is used for the measurement / analysis of the superlattice structure in which the thin films are alternately laminated.

  In the conventional X-ray diffraction measurement analysis method that performs rocking curve measurement / analysis, when the incident angle of X-rays incident on the substrate is changed, the angle is superposed by alternately laminating the substrate crystal and the substrate. By diffracting and emitting X-rays so that X-rays intensify each other where they match the Bragg angle of a thin film with a lattice structure, the diffracted X-ray intensity is specified from the substrate and superlattice structure according to changes in the diffraction angle. The pattern changes. Therefore, by measuring the diffraction X-ray intensity change pattern including crystal structure information by changing the diffraction angle, it is possible to know the values of the stacking period, film thickness, lattice constant, etc. of different types of thin films with superlattice structure from the profile analysis. Can do.

  In the measurement, for example, when a sample is irradiated with an X-ray beam from an X-ray source and the intensity of diffracted X-rays is counted by an X-ray counter, the horizontal axis is expressed as an X-ray diffraction angle and the vertical axis is expressed as an X-ray diffraction intensity. The substrate peak derived from the diffracted X-ray from the substrate and a plurality of satellite peaks derived from the superlattice structure laminated on the substrate appear in the measured X-ray profile.

  On the other hand, in the analysis of the profile by the X-ray diffraction phenomenon, based on the known information of the crystal structure having a superlattice structure on the substrate (the crystal structure information of the substrate and the design information of the substrate and the superlattice structure) The analysis profile corresponding to the measured profile was obtained by theoretical calculation using the four variables characterizing the line profile as parameters, and the fitting process was performed while changing the four variables, and finally the closest match to the measured profile was found. The above four variables at the time are measured values. Thus, by analyzing the actual measurement profile measured by X-ray diffraction, the crystal structure can be grasped numerically.

  More specifically, for example, analysis is performed by theoretical calculation using four values of the lattice constant and film thickness of the quantum well layer constituting the active layer of the strained quantum well semiconductor laser and the lattice constant and film thickness of the barrier layer as parameters. Profiles are obtained, and the parameters of the theoretical calculation are changed so that the pattern of the analysis profile better matches the pattern of the actually measured profile, and fitting of both profiles is performed. Then, the four parameters of the analysis profile best matched by fitting, that is, the lattice constant and film thickness of the quantum well layer and the lattice constant and film thickness of the barrier layer are taken as measured values. Note that methods for obtaining an actual measurement profile and an analysis profile have already been established, and are widely used in academia and industry.

  On the other hand, although the above-described fitting process varies depending on the object, for example, fitting by least square method approximation is well known. In this least square method approximation, fitting is performed so that the square error of the difference between the measured profile and the analysis profile is minimized, and the square root of the difference between both profiles is added evenly over the entire angle range of the profile. A simple algorithm of dividing by the number of samples can be adopted and can be easily automated using a computer. Further, if the initial values of the parameters are set appropriately, the computer program can automatically find the best matching point, which is suitable for searching a relatively wide parameter range.

However, since the actual measurement profile contains a lot of noise and the pattern recognition process is not easy, for example, smoothing (smoothing) processing is performed on the actual measurement profile data in order to find the most consistent point by software. Perform fitting for major peaks (for example, satellite peaks) showing the characteristics of the superlattice structure from the measured profile including noise, and then gradually fitting this feature while gradually reducing this smoothing. (For example, refer to Patent Document 1 and Non-Patent Document 1).
Special Table 2002-532703 “Press Releases” from PANalytical, “New X'Pert Epitaxy software from Philips Analytical makes rocking-curve analysis easier than ever” [searched on December 10, 2004], Internet URL <http://www.panalytical.com/ index.cfm? pid = 21 & itemid = 153 & contentitemid = 12>.

  However, in the above conventional X-ray diffraction measurement analysis method and program, since the least square method approximation is used, the first step fitting for the main peak due to smoothing and the second step fitting while reducing the smoothing. However, since even small peaks and noises are subject to fitting, there is a problem that a plurality of matching points that are originally only one may be obtained depending on conditions.

  On the other hand, the lattice constant related to the crystal of the substrate and the design values such as the arrangement, film thickness, and lattice constant of various thin films of the superlattice structure are known, and the measured profile includes the average peak of the superlattice structure along with the substrate peak. A plurality of other-order satellite peaks separated by a diffraction angle interval corresponding to the period (L) of the superlattice structure around the zero-order satellite peak corresponding to the constant, that is, the sum of the film thicknesses of the alternately stacked thin films Appears multiple times. That is, a specific relationship between the shape characteristics of the actually measured profile and the parameters has been clarified.

  Therefore, by utilizing the obvious relationship between the shape characteristics of the actually measured profile and the four variables (parameters) in this way, if the four variables are aggregated into two independent variables, the profile shape portion having the important information (specific Fitting can be performed by paying attention only to the satellite peak). In this way, simple and reliable analysis can be performed while suppressing the adverse effects of microscopic profile portions such as small peaks and noise.

  Therefore, the present invention does not use small peaks or noises between satellite peaks for fitting, but performs fitting for main satellite peaks that reflect the superlattice structure, and selects specific satellite peaks selected based on known information and measured data. The purpose of this method is to realize an X-ray diffraction measurement analysis method and program that can perform analysis with sufficient accuracy if necessary, and at the same time, without losing generality of the coincidence state of four parameters. The purpose is to realize a two-dimensional display that can be understood with a broad perspective.

  Instead of changing the four variables (parameters) of the analysis profile to match the analysis profile with the actual measurement profile, the inventor of the present application first clearly defines the dependency relationship of these variables from the natural law of superlattice physics. In this way, the knowledge that four variables can be aggregated into two independent variables has been obtained, and an excellent measurement analysis method has been created that is simple, accurate, and without risk of falling into a local optimum value. In addition, this makes it possible to display a bird's-eye view of the four variables as a whole, with a good overall perspective.

  That is, in order to achieve the above object, the present invention (1) makes X-rays incident on a crystal structure having a superlattice structure in which a plurality of first composition thin films and a plurality of second composition thin films are alternately stacked on a substrate. Based on the X-ray diffraction measurement information obtained by detecting the diffracted X-ray, the horizontal axis is expressed as the X-ray diffraction angle and the vertical axis is expressed as the X-ray diffraction intensity, which is derived from the diffracted X-rays from the substrate. A measured profile having a substrate peak and a plurality of satellite peaks derived from the laminated superlattice structure, and the lattice constant and film thickness of the first composition thin film and the lattice constant and film thickness of the second composition thin film as four variables Based on the theoretical calculation of the X-ray diffraction phenomenon using X, the analysis profile expressed as the X-ray diffraction angle on the horizontal axis and the X-ray diffraction intensity on the vertical axis was compared while changing the above four variables, and the best agreement was obtained. Before in state In the X-ray diffraction measurement analysis method in which the four variables of the analysis profile are the measured values of the lattice constant and film thickness of the first composition thin film and the lattice constant and film thickness of the second composition thin film, The period (L) of the superlattice structure is obtained from the interval between a plurality of main satellite peaks in the medium, and the interval between the satellite peak corresponding to the average composition of the superlattice structure in the measured profile and the substrate peak is While obtaining the average lattice constant (a) of the superlattice structure, the film thickness (L1) of one of the first composition thin film and the second composition thin film among the four variables and the first composition thin film or the A setting step of setting an initial value of the lattice constant (a1) of one of the second composition thin films, a period (L) of the superlattice structure, and an average lattice constant (a And the initial value of the film thickness (L1) and the lattice constant (a1) of the one thin film, the film thickness (L2) of the other thin film and the lattice of the first composition thin film or the second composition thin film A variable calculation stage for calculating a value of the constant (a2), a period (L) of the superlattice structure, an average lattice constant (a) of the superlattice structure, a film thickness (L1) of the one thin film, and a lattice constant ( Based on the initial value of a1), the film thickness (L2) of the other thin film, and the value of the lattice constant (a2), an analysis profile creating step for obtaining the analysis profile by the theoretical calculation, the analysis profile, and the actual measurement A comparison stage for comparing the profiles to check the degree of matching between the two profiles; determining whether the degree of matching satisfies a predetermined matching criterion; and determining whether the matching degree is a predetermined matching criterion. Satisfaction In this case, the set values of the film thickness (L1) and the lattice constant (a1) of the one thin film and the values of the film thickness (L2) and the lattice constant (a2) of the other thin film at that time are measured values. When the degree of coincidence does not satisfy a predetermined coincidence criterion, the setting value of either the film thickness (L1) or the lattice constant (a1) of the one thin film is changed. And a determination step for returning to the variable calculation step again.

  In the method of the present invention, first, the period (L) of the superlattice structure and the average lattice constant (a) of the superlattice structure are obtained from the actually measured profile, and based on these values and known information, The initial value of the film thickness (L1) and lattice constant (a1) of one of the two composition thin films is set as the initial value of two of the four variables (setting stage), and the remaining values are based on these values. Are calculated (variable calculation stage), an analysis profile is created by theoretical calculation based on the information obtained so far (analysis profile creation stage). Then, the analysis profile and the actual measurement profile are compared (comparison stage), and when the degree of coincidence of both profiles satisfies the coincidence criterion, the four variables at that time are set as measured values, and the degree of coincidence does not satisfy the above-mentioned criterion. Sometimes, one of the two variable set values is changed and the process returns to the variable calculation stage again (determination stage). Therefore, by consolidating the matching status of the four parameters into two parameters without losing generality, it is possible to converge an appropriate setting of two initial values and a fitting process that only changes one or both of these setting values. The calculation can be executed quickly, and the required measurement accuracy can be ensured.

  In the method of the present invention, (2) in the setting step, the main satellite peak is identified by extracting a periodic isolated peak from the measured profile based on design value information regarding the stacked superlattice structure. It is preferable to do this. As a result, adverse effects of microscopic profile portions such as small peaks and noise can be avoided more effectively, and the processing can be simplified.

  In the method of the present invention, (3) in the setting step, the period (L) and average lattice constant (a) of the superlattice structure obtained from the measured profile, and the film thicknesses of the one and the other thin films The initial values of the film thickness (L1) and the lattice constant (a1) of the one thin film are preferably set based on the design value information of (L1, L2) and the lattice constant (a1, a2). This is because an initial value closer to a measured value to be obtained can be set based on information obtained from an actual measurement profile, design information, or the like.

  In the method of the present invention, (4) in the comparison step, the analysis profile of the zero-order satellite peak corresponding to the average lattice constant (a) of the superlattice structure among the plurality of satellite peaks It is preferable to check the degree of coincidence of the analysis profile and the actual measurement profile for the satellite peaks of other orders among the main satellite peaks in accordance with the actual measurement profile in the vertical axis direction and the horizontal axis direction, respectively. This makes it possible to simplify the matching degree comparison process in consideration of the characteristics of changes in the analysis profile with respect to changes in the four variables.

  In the method of the present invention, (5) in the determination step, one of the thin film thickness (L1) and the lattice constant (a1) is changed to return to the variable calculation step. At this time, it is preferable to finely adjust the set value of the film thickness (L1) of the one thin film while keeping the period (L) of the superlattice structure constant. This is because the period (L) of the superlattice structure can be accurately obtained from the actually measured profile. By fixing this period (L), convergence to the coincidence point can be accelerated.

  In this case, (6) when changing one of the set values of the film thickness (L1) and the lattice constant (a1) of the one thin film and returning to the variable calculation stage again, the period of the superlattice structure ( It is desirable to finely adjust the lattice constant (a1) of the one thin film before finely adjusting the set value of the film thickness (L1) of the one thin film while keeping L) constant. This is because the convergence to the coincidence point can be accelerated considering the correlation in the change of the film thickness (L1) and the lattice constant (a1).

  In the method of the present invention, (7) in the determination step, the value of the film thickness (L1 or L2) of the one or other thin film and the lattice constant (a1 or a2) of the one or other thin film, A distribution diagram showing the degree of coincidence between the analysis profile and the measured profile based on the stored information, stored as points on a contour map like the vertical axis and horizontal axis of the lattice constant and film thickness. On the distribution map, the matching region having the highest degree of matching between the analysis profile and the measured profile, and at least distributed so as to surround the matching region with the matching degree lower than the matching region One circular distribution area is displayed in a visually distinguishable display manner, and the points on the distribution map belong to which of the matching area and the circular distribution area on the distribution map Preferably visually identifiably displayed a degree of the match or. As a result, the degree of coincidence between the analysis profile and the actual measurement profile can be easily seen, and the user can make a quick and accurate determination.

  The present invention also provides (8) X-rays that are diffracted by incident X-rays on a crystal structure having a superlattice structure in which a plurality of first composition thin films and a plurality of second composition thin films are alternately laminated on a substrate. Based on the X-ray diffraction measurement information obtained by detecting the X-ray diffraction angle, the horizontal axis represents the X-ray diffraction angle, the vertical axis represents the X-ray diffraction intensity, the substrate peak derived from the diffracted X-rays from the substrate and the laminated X-ray diffraction using a measured profile having a plurality of satellite peaks derived from a superlattice structure, and the lattice constant and film thickness of the first composition thin film and the lattice constant and film thickness of the second composition thin film as four variables According to the theoretical calculation of the phenomenon, an analysis profile expressed as the X-ray diffraction angle on the horizontal axis and the X-ray diffraction intensity on the vertical axis is compared while changing the four variables, and the analysis profiles in the best match state are compared. Four An X-ray diffraction measurement analysis program having variables as measured values of a lattice constant and a film thickness of the first composition thin film and a lattice constant and a film thickness of the second composition thin film, respectively, Period calculation means (11) for determining the period (L) of the superlattice structure from the interval between a plurality of main satellite peaks in the satellite, the satellite peak corresponding to the average composition of the superlattice structure in the measured profile, and the substrate Mean lattice constant calculation means for obtaining an average lattice constant (a) of the superlattice structure from the distance from the peak, and the film thickness of one of the four composition thin films of the first composition thin film or the second composition thin film (L1) and an initial value setting means for setting an initial value of the lattice constant (a1) of one of the first composition thin film and the second composition thin film, and the circumference of the superlattice structure (L), the average lattice constant (a) of the superlattice structure, and the set values of the film thickness (L1) and the lattice constant (a1) of the one thin film, the first composition thin film or the second composition thin film Among the film thicknesses, variable calculation means for calculating values of the film thickness (L2) and the lattice constant (a2) of the other thin film, the period (L) of the superlattice structure, and the average lattice constant (a ), Based on the set values of the film thickness (L1) and lattice constant (a1) of the one thin film and the values of the film thickness (L2) and lattice constant (a2) of the other thin film, the analysis is performed by the theoretical calculation. Analysis profile creation means for creating a profile, comparison means for comparing the analysis profile and the actual measurement profile to check the degree of matching between both profiles, and whether or not the degree of matching satisfies a predetermined matching criterion The When the degree of coincidence satisfies a predetermined coincidence criterion, the set values of the film thickness (L1) and lattice constant (a1) of the one thin film and the film thickness of the other thin film at that time When the values of (L2) and the lattice constant (a2) are the film thickness measurement values and the lattice constant measurement values, and the degree of coincidence does not satisfy a predetermined coincidence criterion, the film thickness (L1) of the one thin film And a function of a determination unit that changes any set value of the lattice constant (a1) and causes the variable calculation unit to execute the calculation again.

  By this program, the matching state of four parameters is aggregated into two parameters without losing generality, so that it is possible to set two appropriate initial values and only change one or both of these setting values. Can be executed quickly in terms of convergence calculation, and the required measurement accuracy can be ensured.

  In the program of the present invention, (9) the initial value setting means obtains the periodicity corresponding to the period (L) of the superlattice structure from the measured profile based on the design value information regarding the stacked superlattice structure. It is preferable to identify the main satellite peak by extracting a plurality of isolated peaks. In this way, the adverse effects of microscopic profile portions such as small peaks and noise can be avoided more effectively, and the processing can be simplified.

  In the program of the present invention, (10) the initial value setting means includes the period (L) and average lattice constant (a) of the superlattice structure obtained from the measured profile, and the one and the other thin films. Based on the design value information of the film thickness (L1, L2) and the lattice constant (a1, a2), the initial value of the film thickness (L1) and the lattice constant (a1) of the one thin film may be set. With this configuration, an initial value closer to the measurement value to be obtained can be set based on information obtained from an actual measurement profile, design information, or the like.

  Further, in the program of the present invention, (11) the comparison means sets the analysis profile for the zero-order satellite peak corresponding to the average lattice constant (a) of the superlattice structure among the plurality of satellite peaks. It is preferable to execute a simulation to match the actual measurement profile in the vertical axis direction and the horizontal axis direction, respectively, and examine the degree of coincidence of the analysis profile and the actual measurement profile for the satellite peaks of other orders among the main satellite peaks. This makes it possible to simplify the matching degree comparison process in consideration of the characteristics of changes in the analysis profile with respect to changes in the four variables.

  In the program according to the present invention, further, (12) the determination means changes one of the set values of the thin film thickness (L1) and the lattice constant (a1) of the one thin film, and recalculates the variable calculation means. The initial value setting means may finely adjust the set value of the film thickness (L1) of the one thin film while keeping the period (L) of the superlattice structure constant. This is because the period (L) of the superlattice structure can be accurately obtained from the actually measured profile. By fixing this period (L), it is possible to speed up the convergence to the coincidence point.

  In this case, further, (13) When the determination unit changes any one of the film thickness (L1) and the lattice constant (a1) of the one thin film, and causes the variable calculation unit to execute the calculation again Before the initial value setting means finely adjusts the set value of the film thickness (L1) of the one thin film while keeping the period (L) of the superlattice structure constant, the lattice constant of the one thin film is set. It is desirable to finely adjust (a1). Thereby, based on the correlation in the change of the film thickness (L1) and the lattice constant (a1), the convergence to the coincidence point can be accelerated.

  In the program of the present invention, (14) the computer is provided with values of the film thickness (L1 or L2) of the one or other thin film and the lattice constant (a1 or a2) of the one or other thin film. Storage means for storing the lattice constant and film thickness as points on a contour map-like distribution map with the vertical and horizontal axes, and the degree of coincidence between the analysis profile and the actual measurement profile based on the storage information of the storage means It is preferable to realize a function of a distribution map creating means for generating image information of a distribution map indicating With this program, the distribution of a plurality of measurement values can be easily grasped visually as the distribution of the degree of coincidence between the analysis profile and the actual measurement profile.

  In this case, further, (15) the distribution map creating means, based on the storage information of the storage means, the matching region having the highest degree of matching between the analysis profile and the actually measured profile, and the degree of matching Preferably, at least one annular distribution region distributed so as to surround the matching region lower than the region is displayed in a visually distinguishable display mode. As a result, the degree of coincidence between the analysis profile and the actual measurement profile can be easily seen, and the user can make a quick and accurate global determination.

According to the program of the present invention, (16) X-rays are incident on a crystal structure having a superlattice structure in which a plurality of first composition thin films and a plurality of second composition thin films are alternately stacked on a substrate at different angles. When the profile is displayed on the basis of the measurement information, the measured profile of the diffracted X-ray intensity varying with the angle, the lattice constant (a1) and the film thickness (L1) of the first composition thin film as the four variables, and the first The analysis profile of the diffraction X-ray intensity that changes according to the angle, which is displayed based on the theoretical calculation using the lattice constant (a2) and the film thickness (L2) of the two-component thin film, The four variables of the analysis profile in the best match state are compared while changing the variables, and the lattice constant and the film thickness of the first composition thin film and the second composition thin An X-ray diffraction measurement analysis program to the respective measurement values of the lattice constant and the film thickness, when n is a positive integer, n number of the angle values _{(x 1, x 2, ···} x _n ) and the measured values (g ₁ , g ₂ ,..., g _n ) of _n diffraction X-ray intensities corresponding to the angle are sequentially stored in a memory, and stored in the memory. A measured profile creating means (42) for creating a measured profile of the diffraction X-ray intensity that changes according to the angle based on the measured data in a predetermined profile display format capable of being displayed and output, and a plurality of the measured profiles in the measured profile Period calculation means (47) for determining the period (L) of the superlattice structure from the interval between main satellite peaks, and satellite peaks appearing in the measured profile corresponding to the average composition of the superlattice structure Mean lattice constant calculating means (47) for obtaining an average lattice constant (a) of the superlattice structure from an interval with a substrate peak appearing in the actual measurement profile derived from the substrate, and the first composition thin film or the second thin film The initial value of the film thickness (L1 or L2) of one thin film of the composition thin films and the lattice constant (a1 or a2) of one thin film of the first composition thin film or the second composition thin film is expressed by the four variables ( initial value setting means (44) for setting as initial values of two variables of a1, L1, a2, and L2), a period (L) of the superlattice structure, and an average lattice constant (a) of the superlattice structure And the first composition which is the remaining two variables of the four variables (a1, L1, a2, L2) from the set value of the film thickness (L1) and the lattice constant (a1) of the one thin film. The other of the thicknesses of the thin film or the second composition thin film Variable calculation means (48) for calculating the film thickness (L2) and the lattice constant (a2) of the thin film, the set values of the film thickness (L1) and the lattice constant (a1) of the one thin film, Specific satellites having different orders among the plurality of satellite peaks, with the film thickness (L2) and lattice constant (a2) values of the other thin film calculated by the variable calculation means (48) as the four variables. M angle values (x _i , x _j ,..., X _{i + m−1} ), which are positive integers less than n that specify the angle range corresponding to the peak, where i and j are smaller than m, respectively. Analysis profile creation means (49) for creating the analysis profile by calculating the value (f _i , f _j ,... F _{i + m-1} ) of the diffraction X-ray intensity for the positive integer) by the theoretical calculation. And the analysis profile and the actual measurement profile A comparison means (51) for comparing a plurality of satellite peaks with respect to specific satellite peaks of different orders and checking the degree of coincidence of both profiles, and the degree of coincidence satisfies a predetermined coincidence criterion When the degree of coincidence satisfies a predetermined coincidence criterion, the four variables (a1, L1, a2, L2) of the analysis profile at that time are used as the film thickness of the one thin film. When the degree of coincidence does not satisfy a predetermined coincidence criterion, the film thickness (L1) and the lattice of the one thin film are output. The function of the determination means (52) for changing any set value of the constant (a1) and causing the variable calculation means to execute the calculation again is realized by using a computer. And it is characterized in and.

  By this program, the matching state of four parameters is aggregated into two parameters without losing generality, so that it is possible to set two appropriate initial values and only change one or both of these setting values. Can be executed quickly in terms of convergence calculation, and the required measurement accuracy can be ensured.

  According to the present invention, small peaks and noises between satellite peaks are not used for fitting, and initial values of appropriate two variables are set for specific satellite peaks selected based on known information and measured data. Since the fitting process that only changes one or both of the initial values is performed quickly in terms of convergent calculation, a fast and effective fitting is performed on the main satellite peak reflecting the superlattice structure, which is sufficient if necessary. An X-ray diffraction measurement analysis method and program capable of analyzing the accuracy can be realized. In addition, by consolidating the coincidence state of the four parameters into two parameters without losing generality, it is possible to realize a two-dimensional display that allows the consensus state to be understood globally with good visibility without losing generality. .

  In other words, the present invention clarifies the dependency relationship of the four variables in the analysis profile, thereby consolidating the four variables into two independent variables, making it easy, accurate, and excellent without risk of falling into a local optimum value. This is a creation of an analysis method, which makes it possible to display a bird's-eye view of the four variables as a whole, with a good overall perspective.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  1 to 9 are diagrams showing a measurement analysis apparatus for carrying out an X-ray diffraction measurement analysis method according to one embodiment of the present invention, which will be described later according to the X-ray diffraction measurement analysis program of the present invention. Execute the process.

  First, the configuration will be described.

  As schematically shown in FIGS. 1 and 2, in this measurement apparatus, the sample substrate 10 supported by the first turntable 1 is irradiated with the X-ray beam from the X-ray source 20 and the sample substrate. An X-ray diffracted at 10 is detected by an X-ray counter 30 supported on the second turntable 2, and an optical system for measuring the X-ray intensity is configured. The first turntable 1 can be rotated (reciprocatingly rotated) at an angular velocity ω so that the incident angle of the X-ray beam to the sample substrate 10 changes, and the second turntable 2 has the same central axis as the first turntable 1. It can be rotated around at an angular velocity different from that of the first turntable 1. These turntables 1 and 2 are driven to rotate by known driving means 3 and 4 corresponding to each of the turntables 1 and 2 and at an angle θ (viewing angle) formed by the substrate surface of the rotating sample substrate 10 and the incident X-ray beam. On the other hand, rotation is controlled so that the angle formed by the X-ray receiving axis of the X-ray counter 30 with respect to the X-ray beam irradiation axis (indicated by a one-dot chain line in FIG. 1) is always maintained at the angle 2θ. Yes. That is, the X-ray counter 30 is always arranged in the direction of the diffracted emission angle with respect to the change in the incident angle of the X-ray beam with respect to the sample substrate 10.

  The sample substrate 10 is a crystal structure having a superlattice structure in which a plurality of first composition thin films and a plurality of second composition thin films are alternately stacked on the substrate, for example, on an indium phosphide (hereinafter referred to as InP) substrate. A thin film of different types of indium gallium arsenide phosphorus (InGaAsP) is stacked, and it has a multiple quantum well (MQW) structure in which a barrier layer serving as an active layer of a semiconductor laser and a thin film of a quantum well layer (for example, about 60 Å) are stacked. is doing.

  The X-ray source 20 includes, for example, an X-ray tube 21, a bending mirror 22, and a monochromator 23. The X-ray bundle generated by the X-ray tube 21 is converged on the measurement surface of the sample substrate 10 by the bending mirror 22. The monochromator 23 is used to make a single color in a specific wavelength range. The X-ray counter 30 is constituted by, for example, a scintillation counter, and outputs a count value corresponding to the intensity of the diffracted X-ray.

  As shown in FIG. 2, the drive circuit 5 of the X-ray tube 21 of the X-ray source 20 and the drive means 3 and 4 of the first turntable 1 and the second turntable 2 are connected to the measurement analysis control device 40, respectively. The measurement analysis control device 40 controls the operation of the measurement system as described above. Further, the measurement information from the signal processing circuit 31 of the X-ray counter 30 and the detection information of the rotational position detectors 6 and 7 of the first rotary table 1 and the second rotary table 2 are respectively taken into the measurement analysis control device 40. The measurement analysis control device 40 executes a predetermined X-ray diffraction measurement analysis program on the basis of the input information and the setting input or operation input from the setting / input unit 406, and displays a known display device. The unit 407 is configured to display and output a diffracted X-ray pattern having the horizontal axis as the diffraction angle (in seconds) and the vertical axis as the diffracted X-ray intensity, and to output the display image information to the outside.

  Although a detailed hardware configuration is not shown in the drawing, the measurement analysis control device 40 is roughly divided into, for example, a CPU (Central Processing Unit) 401, a ROM (Read Only Memory) 402, a RAM (Random Access Memory) 403, and an input / output interface circuit 404. In addition, an auxiliary storage device 405 such as a disk drive can be built in, and the setting / input unit 406 and the display unit 407 are attached. In addition, the measurement analysis control device 40 receives count information from the signal processing circuit 31 of the X-ray counter 30 while the CPU 401 exchanges data with the RAM 403 in accordance with a control program stored in the ROM 402 and the auxiliary storage device 405. Based on the detection information of the rotational position detectors 6 and 7, the input information from the setting / input unit 406, etc., an arithmetic process for grasping the diffraction X-ray intensity and the diffraction angle is executed, and a functional block is shown in FIG. The function of each part is demonstrated.

As shown in FIG. 3, in the measurement analysis control device 40, information on the diffraction X-ray intensity and the diffraction angle at that time is sequentially stored in the actual measurement data storage unit 41. That is, X-rays obtained by detecting X-rays incident on the crystal structure of the sample substrate 10 and diffracted by the X-ray counter 30 while changing the incident angle of the X-ray beam to the sample substrate 10 as described above. The line diffraction measurement information is sequentially stored in the actual measurement data storage unit 41. In this case, specifically, for example, n (positive integer) angle values x ₁ , x ₂ ,... X _n and n diffraction X-ray intensity measured values g ₁ corresponding to the angles. , G ₂ ,... _Gn are sequentially stored in the memory.

  Based on the data stored in the actual measurement data storage unit 41, the actual measurement profile creation unit 42 represents an actual measurement profile represented by the X-ray diffraction angle on the horizontal axis and the X-ray diffraction intensity on the vertical axis, that is, a diffraction X-ray diagram obtained from the actual measurement data. Is created by a known graphic processing. This actual measurement profile is displayed as a result of X-ray diffraction measurement as a graph with the angle on the horizontal axis and the X-ray intensity on the vertical axis. For example, as shown in FIG. The maximum sharp peak (substrate peak) P10 corresponding to the crystal lattice constant of the substrate layer is shown as a relative angle (seconds) around the center, and the diffracted X-ray intensity on the vertical axis indicates the number of counts per second (counts / sec ).

  As shown in FIG. 4, the actual measured profile includes a plurality of satellite peaks derived from the superlattice structure laminated thereon, in addition to the substrate peak P10 derived from the diffracted X-rays from the substrate layer of the sample substrate 10. P20 (0th order satellite peak), P21 (-1st order satellite peak), P22 (+ 1st order satellite peak), P23 (+ secondary satellite peak), etc. appear at angular intervals corresponding to the stacking period L of different thin films in the superlattice. . The other peaks in FIG. 4 are derived from other thin films included in the superlattice structure, for example, a plurality of indium gallium arsenide phosphorous (InGaAsP) thin film layers (for example, about 100 angstroms) constituting the light guide layer of the semiconductor laser. This is based on the diffracted X-rays.

  Design information of the superlattice structure to be the sample substrate 10 (stacking cycle of different thin films stacked alternately, film thickness and lattice information of each layer, lattice information, arrangement, etc.) is preset and stored in the design information storage unit 43. .

  The storage information of the design information storage unit 43 is taken into the specific peak selection unit 45 together with the actual measurement profile information from the actual measurement profile creation unit, and the specific peak selection unit 45 is based on the design value information regarding the superlattice structure stacked. In the actual measurement profile, a region where a plurality of isolated peaks having periodicity corresponding to the period L of the superlattice structure is identified.

  Here, the conditions for specifying the occurrence region of the specific peak are stored in the peak specifying condition storage unit 46. This condition is based on, for example, information on the magnitude relationship between the lattice constants of different types of thin films constituting the superlattice and the crystal lattice constant of the substrate layer of the sample substrate 10 and the characteristics of the appearance of satellite peaks that differ accordingly. Thus, there is a probability that an isolated satellite peak (for example, satellite peaks P20 and P21 shown in FIG. 4 that form an independent peak waveform with little interference with other large peaks) is generated. This is a condition for specifying a high region in the diffraction angle range. For example, when the lattice constant of the first composition thin film is larger than the lattice constant of the substrate layer (InP) and the lattice constant of the second composition thin film has a design specification equivalent to the lattice constant of the substrate layer, an isolated satellite peak is usually used. Appear on the left side of the substrate peak (in a specific region of a predetermined angle range corresponding to the superlattice lamination period in the minus side angle region), or the lattice constant of the first composition thin film is the lattice constant of the substrate layer (InP). In the case of an equivalent design specification in which the lattice constant of the second composition thin film is smaller than the lattice constant of the substrate layer, the isolated satellite peak usually corresponds to the stacking period of the superlattice on the right side of the substrate peak (plus-side angular region). A design in which the lattice constant of the first composition thin film is larger than the lattice constant of the substrate layer (InP) and the lattice constant of the second composition thin film is smaller than the lattice constant of the substrate layer. In the case of like, generally isolated satellite peak appears more on each side of the substrate peak. Then, there is a general tendency that these isolated satellite peaks become satellite peaks effective for fitting. Based on such conditions, it is possible to determine a specific satellite peak generation region effective for fitting.

  In addition, the process of extracting the isolated satellite peak by the specific peak selection unit 45 is performed, for example, by calculating the average diffracted X-ray intensity in a unit of a predetermined angle range that is sufficiently narrower than the interval between the satellite peaks in the generation region of the specific satellite peak. The satellite peaks of each order can be extracted. At this time, the interval between the satellite peaks can be generally predicted based on the design information, and a relatively small number of samplings are required for identifying the satellite peaks of each order (identifying by the angle range). In addition, when the 0th-order, −1st-order, and + 1st-order satellite peaks are buried in the substrate peaks or the peaks caused by other layers, other isolated satellite peaks are used.

  The profile information regarding the main satellite peak specified by the specific peak selection unit 45 based on the storage information of the peak specification condition storage unit 46 is sent to the period / average lattice constant calculation unit 47, where the first composition The stacking period of the thin film and the second composition thin film, that is, the stacking period L of the superlattice composed of the well layer and the barrier layer of the multiple quantum well structure and the average lattice constant a of the superlattice structure stacked in multiple layers are calculated.

In the period / average lattice constant calculation unit 47, the stacking period L of the first composition thin film and the second composition thin film is different from the angular interval of the main satellite peak in the actual measurement profile, specifically, for example, with a specific order. From the diffraction angles θ _i and θ _{j at} which the satellite peaks P20 and P21 appear and the wavelength of the X-ray, it can be directly and accurately calculated by the following equation (1). Here, i and j are the orders of the satellite peaks.

L = (i + j) λ / (2 (sin θ _i −sin θ _j )) (1)
Here, with respect to the stacking period L of the first composition thin film and the second composition thin film, the film thickness of the first composition thin film (eg, well layer) is L1, and the film thickness of the second composition thin film (eg, barrier layer) is L2. Then, these can be expressed by the following formula (2).

L = L1 + L2 (2)
Accordingly, the two parameters L1 and L2 have a dependency relationship. When L2 is determined as a parameter, L1 is determined as in the following equation (3), and conversely, when L1 is determined, L2 is automatically determined.

L1 = L−L2 (3)
In the period / average lattice constant calculation unit 47, a diffraction angle at which a zero-order satellite peak P20 corresponding to the average lattice constant a, which is the average composition of the superlattice structure, among the plurality of satellite peaks in the actual measurement profile appears, From the difference from the diffraction angle at which the substrate peak P10 due to the crystal of the InP substrate layer of the sample substrate appears, the average lattice constant a can be directly calculated with high accuracy. This average lattice constant a can also be expressed by the following equation (4).

a = (a1 · L1 + a2 · L2) / (L1 + L2) (4)
In this equation (4), the lattice constants of the quantum well layer and the barrier layer are indicated by a1 and a2, respectively, and can be expressed as follows when a1 is selected as a parameter.

a1 = (a · L−a2 · L2) / (L−L2) (5)
As described above, the period / average lattice constant calculation unit 47 determines the function of the period calculation means for obtaining the period L of the superlattice structure from the interval between a plurality of main satellite peaks and the average composition of the superlattice structure in the measured profile. And a function of an average lattice constant calculating means for obtaining an average lattice constant a of the superlattice structure from an interval between the corresponding satellite peak P20 and the substrate peak P10 appearing in the actual measurement profile derived from the InP substrate.

  By the way, when all the values on the right side of the above equation (4) are known, that is, when the lattice constant a2 is determined, another lattice constant a1 is uniquely determined by the dependency. Of course, the reverse is also true, and when the lattice constant a1 is determined, the lattice constant a2 is automatically determined. That is, it can be said that four parameters can be aggregated into two parameters by the dependency relationship.

  Therefore, in the initial value setting / changing unit 44 (initial value setting means), two parameters among the four parameters (variables) L1, L2, a1, and a2, that is, the first composition thin film or the second composition thin film. The initial value of the film thickness L1 of one thin film and the initial value of the lattice constant a1 of one thin film of the first composition thin film or the second composition thin film are set as described later, and the set value is changed. It is supposed to be. When the initial value of the film thickness L1 and the initial value of the lattice constant a1 are set, the initial value of the film thickness L2 of the other thin film of the first composition thin film or the second composition thin film is determined from the above-described dependency relationship. The lattice constant a2 of the other thin film of the first composition thin film or the second composition thin film is uniquely determined.

  The initial value setting / changing unit 44 also determines the values of the period L and average lattice constant a of the superlattice structure obtained from the measured profile, the design values thereof, the film thicknesses L1 and L2 of the one and the other thin films, and the lattice. Based on the design value information such as the design values of the constants a1 and a2, the initial value of the film thickness L1 and the lattice constant a1 of the one thin film is also considered in consideration of the deviation from the design value of the period L and the average lattice constant a. Are set to maintain the same mutual ratio as the design value, for example. Further, the initial value setting / changing unit 44 sequentially changes (increases or decreases) the set initial value in units of a predetermined fine adjustment amount when receiving an update command from a condition determination unit 52 (determination unit) described later. It has a function to make it.

  The variable calculation unit 48 (variable calculation means) sets the initial values of the thin film thickness L1 and the lattice constant a1 set by the initial value setting / change unit 44 or the changed film thickness L1 and the lattice constant a1. Based on each value and the period L of the superlattice structure calculated by the period / average lattice constant calculation unit 47 and the value of the average lattice constant a of the superlattice structure, the above expressions (3) and (5) are shown. Under such conditions, the film thickness L2 and the lattice constant a2 of the other thin film constituting the superlattice are calculated.

The four parameters obtained as described above, that is, the initial values of the film thickness L1 and the lattice constant a1 of the one thin film, and the values of the film thickness L2 and the lattice constant a2 of the other thin film are: Each is taken into the analysis profile creation unit 49, and the analysis profile creation unit 49 uses the four parameters L 1, L 2, a 1, a 2 to calculate the horizontal axis by the theoretical calculation of the X-ray diffraction phenomenon using these values. An analysis profile is created in which the X-ray diffraction angle and the vertical axis represent the X-ray diffraction intensity. At this time, since the profile creation area is specified as a specific area, a specific satellite peak having a different order among a plurality of main satellite peaks based on the four parameters L1, L2, a1, and a2 (variables). X angle values x _i , x _j ,..., X _{i + m-1} (where i and j are positive numbers smaller than m, respectively), which are positive integers less than n that specify the angle range corresponding to With respect to (integer), an analysis profile is created by calculating the diffraction X-ray intensity values f _i , f _j ,... F _{i + m−1} by the theoretical calculation.

The comparison unit 51 takes in the data of the analysis profile and the actual measurement profile from the actual measurement profile creation unit 42 and the analysis profile creation unit 49, compares both profiles, and checks the degree of coincidence of both profiles. Here, specific satellite peaks having different orders are compared to examine the degree of coincidence between the two profiles. This comparison is performed, for example, by obtaining the mean square error E for the satellite peak region to be compared. This mean square error E is In selected individual peaks forming angle range of a particular satellite peaks as compared, the value of the measured profile of each sampling point, for example, _{f i (i = 1,2, ···} n) and the analysis profile value g _i The square value of the difference (f _i −g _i ) is equally added to obtain the square root and divided by the number of samples n. That is, E = {(f ₁ −g ₁ ) ² + (f ₂ −g ₂ ) ² +... + (F _n −g _n ) ² } ^1/2 / n is used as the comparison result.

  The comparison result in the comparison unit 51 is taken into the condition determination unit 52 (determination means). In the condition determination unit 52, the mean square error E for each satellite peak to be compared is less than or equal to a preset allowable value. It is determined whether it has been reached. That is, it is determined whether or not the degree of coincidence satisfies a predetermined coincidence criterion (allowable value or less), and when the degree of coincidence satisfies a predetermined coincidence criterion, the one thin film at that time The set values of the film thickness L1 and the lattice constant a1 and the values of the film thickness L2 and the lattice constant a2 of the other thin film are the measured values of the film thickness and the lattice constant, respectively. On the other hand, when the degree of coincidence between both profiles does not satisfy a predetermined coincidence criterion, one of the set values of the thin film thickness L1 and the lattice constant a1 is initially set in units of a predetermined fine adjustment amount. The value is changed / changed by the value setting / changing unit 44, and the variable calculation unit 48 is made to execute the variable calculation again. Further, when the result does not satisfy the coincidence criterion again, the remaining one set value among the film thickness L1 and the lattice constant a1 of the one thin film is transferred to the initial value setting / changing unit 44 in a predetermined fine adjustment amount unit. Then, the variable calculation unit 48 executes the calculation of the variable again. After that, when the coincidence criterion is not satisfied, first, the setting value of any one of the film thickness L1 of the one thin film and the lattice constant a1 is changed from the previous setting value in a predetermined fine adjustment amount unit, Next, the remaining one previous set value of the film thickness L1 and the lattice constant a1 of the one thin film is changed again in units of a predetermined fine adjustment amount, and the recalculation of the variable is executed. Further, when the re-creation (simulation) of the analysis profile by changing such a variable is not performed even after a predetermined number of times, the sample substrate 10 is determined to be defective.

  In the present embodiment, the condition determination unit 52 cooperates with the comparison unit 51 to select a zero-order satellite peak (only the peak point) corresponding to the average lattice constant a of the superlattice structure among the plurality of satellite peaks. ), A simulation for matching the analysis profile to the actual measurement profile in the vertical axis direction and the horizontal axis direction is executed first, and the simulation processing unit of the comparison means is configured by these.

  Therefore, when the condition determination unit 52 changes the set value of either the film thickness L1 or the lattice constant a1 of the one thin film and causes the variable calculation unit 48 to execute the calculation again, the initial value setting / change unit 44 and The variable calculation unit 48 finely adjusts the set value of the film thickness L1 of the one thin film while keeping the period L of the superlattice structure constant, and further, the one of the ones while keeping the period L of the superlattice structure constant. Prior to fine adjustment of the set value of the thin film thickness L1, the lattice constant a1 of the one thin film is finely adjusted.

  The satellite peak selected as a comparison target in the comparison unit 51 is a zero-order satellite peak at the first time and a satellite peak having a different order from this (for example, a negative-side primary satellite peak). After the set value is changed so that the mean square error E is equal to or less than a predetermined value, only satellite peaks having different orders may be compared. That is, the comparison unit 51 is an error analysis unit that examines the degree of matching mainly for satellite peaks of other orders after the simulation processing for matching both profiles for the zero-order satellite peaks.

  As described above, the measurement analysis control device 40, in accordance with the X-ray diffraction measurement analysis program stored in the auxiliary storage device 405, changes the four parameters for specifying the analysis profile while consolidating them into two, and the actual measurement profile and the analysis profile. And the four variables of the analysis profile in a state where the two profiles are the best match are output as the measured values of the lattice constants a1 and a2 and the film thicknesses L1 and L2 of the first and second composition thin films.

  In addition, when the measurement analysis control device 40 repeats the above-described measurement analysis for a plurality of sample substrates 10, the condition determination unit 52 determines that the degree of matching satisfies a predetermined matching criterion. Even when a defect is determined, the value of the film thickness L1 or L2 of the one or other thin film and the value of the lattice constant a1 or a2 of the one or other thin film is The coincidence distribution map with the axis and the horizontal axis, for example, a contour map-like distribution diagram as shown in FIG. 5 or a stepwise change in luminance, color or color density according to the coincidence as shown in FIG. When the points on the distribution diagram (indicated by circles in FIG. 5) are stored and accumulated in the auxiliary storage device 405 (distribution data storage means), and the measurement and analysis are performed on a plurality of sample substrates 10, the distribution is obtained. Based on the data storage information, the function of the distribution map creating means for generating the distribution image information of the degree of coincidence between the analysis profile and the measured profile, and the distribution image information generated by the function of the distribution map creating means are displayed on the display unit 407. Or it has the function of the output means to output outside, respectively.

  As shown in an example in FIG. 5, the measurement analysis control device 40 serving as a distribution diagram creation unit is based on the distribution data storage information in the auxiliary storage device 405, and the matching region has the highest degree of matching between the analysis profile and the actual measurement profile. 101 and a display in which the degree of coincidence is lower than the coincidence region 101 and at least one annular distribution region distributed so as to surround the coincidence region 101, for example, four annular distribution regions 102, 103, and 104 can be visually distinguished It is generated in the form. Here, the visually distinguishable display mode is, for example, a display area divided by different colors, darkness, one or more coincidence contours, and a different fill condition as shown (for example, different shading). As shown in FIG. 6, the color is gradually changed from the inner side where the degree of coincidence is high to the outer side where the degree of coincidence is low. May be. In FIG. 6, a large number of distribution data points are not shown so as to be individually visible, and a large number of annular distribution regions having the same color (for example, yellow) and the same luminance indicating the degree of distribution are displayed steplessly by gradation. However, the data itself is stored as a point having one coordinate in the distribution map. Further, as shown in FIG. 5, the center of the coincidence area 101 (the white elliptical portion having the highest luminance in FIG. 6) is a perfect coincidence point of the analysis / measurement profile, and the deviation increases as the distance from this point increases. Become. Therefore, in the four annular distribution regions 102, 103, and 104 distributed so as to surround the coincidence region 101 (in FIG. 6, the annular portion that gradually becomes black toward the outside surrounding the white elliptical portion), both profiles are slightly shifted. An intermediate region 103 showing a state in which there is a gap in the other part of the profile where both profiles are partially close from an inner region 102 showing the state, and an outside showing a state in which there is a clear gap between both profiles The region 104 is gradually moved to the outer region 104, and in the outer side, both profiles are separated from each other so that there is a large gap (a dark black portion in FIG. 6).

  In this embodiment, when the thickness L1 of the well layer which is one thin film is determined, the film thickness L2 of the barrier layer which is the other thin film is uniquely determined. Therefore, as shown in FIG. The thicknesses of the two thin films are shown on one axis of the degree distribution diagram, for example, the horizontal axis.

  Next, an embodiment of an X-ray diffraction measurement analysis method implemented using the above-described measurement analysis apparatus will be described.

  FIG. 7 is a flowchart showing a schematic flow of an X-ray diffraction measurement analysis program executed by the measurement analysis apparatus of this embodiment, and the method of the present invention can be implemented by this program.

  First, after making preparations such as storage of design value information in the design information storage unit 43 and condition input to the peak specifying condition storage unit 46 (step S10), measurement is performed (step S11), and an actual data storage unit The actual measurement data is sequentially stored as storage information in 41 (step S12).

  Next, based on the stored information in the actual measurement data storage unit 41, the actual measurement profile creation unit 42 creates an actual measurement profile (step S13).

  Next, the specific peak selection unit 45 specifies a region where a specific satellite peak having a different order is isolated among the plurality according to the storage conditions of the peak specification condition storage unit 46 (step S14), and the period / average lattice constant calculation unit 47 The stacking period L of the superlattice structure is obtained from the interval between the plurality of satellite peaks corresponding to the average composition of the superlattice structure, for example, satellite peaks P20 and P21 (step S15), and the main satellite peak in the measured profile is For example, the average lattice constant a of the superlattice structure is obtained from the interval between the zeroth-order satellite peak P20 and the substrate peak P10 (step S16).

  Next, in the initial value setting / changing unit 44, among the four variables, the initial value of the film thickness L1 of one of the first composition thin film and the second composition thin film and the first composition thin film or the second composition thin film The initial value of the lattice constant a1 of one thin film is set based on the storage information in the design information storage unit 43 and the calculation results L and a in the period / average lattice constant calculation unit 47 (step S17; setting stage). ). This initial value is the same as the design value when the stacking period L and the average lattice constant a of the superlattice structure obtained from the actual measurement profile are close to the design value, but the initial value of the superlattice structure obtained from the actual measurement profile. When the stacking period L and the average lattice constant a are deviated from the design values, they are slightly adjusted to the deviating side in units of the fine adjustment amount.

  Next, the variable calculation unit 48 calculates the second composition thin film or the second composition thin film from the period L of the superlattice structure, the average lattice constant a of the superlattice structure, and the set values of the film thickness L1 and the lattice constant a1 of the one thin film. Of the film thicknesses of one composition thin film, the film thickness L2 and the lattice constant a2 of the other thin film are calculated (step S18; variable calculation stage).

  Next, in the analysis profile creation unit 49, the period L of the superlattice structure, the average lattice constant a of the superlattice structure, the set values of the film thickness L1 and the lattice constant a1 of the one thin film, and the film thickness L2 of the other thin film Based on the value of the lattice constant a2, an analysis profile is created by the theoretical calculation (step S19; analysis profile creation stage).

  Next, the comparison unit 51 compares the created analysis profile and the actual measurement profile to check the degree of coincidence of both profiles (step S20; comparison stage).

  Next, the condition determination unit 52 determines whether or not the degree of matching for the zeroth-order satellite peak satisfies a predetermined matching criterion (step S21), and the degree of matching satisfies a predetermined matching criterion. When it is determined whether or not the degree of coincidence for satellite peaks having different orders, for example, −1st order satellite peaks, satisfies a predetermined coincidence criterion (step S22). Of course, if necessary, there may be a step (step S23) of determining the degree of coincidence for the secondary satellite peak (for example, the -secondary satellite peak).

  Here, when the degree of coincidence satisfies a predetermined coincidence criterion, the set values of the film thickness L1 and the lattice constant a1 of the one thin film and the values of the film thickness L2 and the lattice constant a2 of the other thin film at that time The measurement results are output to the display unit 407 as the respective film thickness measurement values and lattice constant measurement values (step S24).

  On the other hand, when the degree of coincidence does not satisfy a predetermined coincidence criterion, one of the set values of the thin film thickness L1 and the lattice constant a1 is changed by the initial value setting / changing unit 44. (Step S26), the process returns to the variable calculation stage in the variable calculation unit 48 again (step S18).

  Next, an analysis profile is created again (step S19), and the check in the comparison unit 51 is executed again for the zeroth-order satellite peak P20 corresponding to the average lattice constant a of the superlattice structure among the plurality of satellite peaks (step S19). S21). As described above, the initial value setting / changing unit 44 changes the setting value so that the analysis profile is matched to the actual measurement profile in the vertical axis direction and the horizontal axis direction for the peak point of the zeroth-order satellite peak P20 first. Let it run. At this time, for example, the zero-order peak intensity is first adjusted, and if the angular interval between the specific satellite peaks P20 and P21 does not match between the analysis profile and the actual measurement profile, the period L is adjusted to make the interval closer. . Such a change in the set value brings about a change in the analysis profile as shown on the left and right sides in FIG. That is, when the period L is increased, the satellite peaks approach each other as shown on the right side of the figure, and when the period L is reduced, the satellite peaks move away as shown on the left side of the figure.

  Then, when the coincidence criterion is satisfied for the peak point of the zeroth-order satellite peak P20, the degree of coincidence between the analysis profile and the actual measurement profile for the satellite peak of another order among the main satellite peaks, for example, the primary satellite peak P21 is set. Confirmation is made (steps S22 and S23), and if they do not match, the initial value setting / changing unit 44 changes the setting value (step S26).

  During this time, it is determined whether or not the set value change of the film thickness L1 and the lattice constant a1 of the one thin film has reached a predetermined number of times (step S25). The result is output to the display unit 407 (step S27).

  In the condition determination unit 52, when changing the set value of either the film thickness L1 of the one thin film or the lattice constant a1 and executing the calculation in the variable calculation unit 48 again, the period of the superlattice structure The set value of the film thickness L1 of the one thin film is finely adjusted while keeping L constant (step S26). Further, before finely adjusting the set value of the film thickness L1 of the one thin film while keeping the period L of the superlattice structure constant, the coincidence criterion is satisfied for the peak point of the zero-order satellite peak P20. Then, the lattice constant a1 of the one thin film is finely adjusted (step S26). Such a change in the set value brings about a change in the analysis profile as shown in the upper and lower parts in FIG. That is, when the lattice constant is increased, as shown in the upper side of the figure, the envelope EN in contact with the plurality of satellite peaks is inclined counterclockwise in the figure, and when the lattice constant is reduced, as shown in the lower side of the figure. In addition, the analysis profile changes so that the envelopes EN in contact with the plurality of satellite peaks are inclined clockwise in FIG. Therefore, when the lattice constant is adjusted, the effect becomes stronger as the satellite peak has a higher order.

  By such a series of setting changes of the film thickness L1 and the lattice constant a1, the analysis profile is the same as that shown in FIG. Convergently change from the initial initial state stage shown in a) to the stage satisfying the coincidence criteria shown in FIG. 10C through the zero-order satellite peak matching stage shown in FIG. become.

  On the other hand, when the measurement result is output to the display unit 407 (step S24) or the failure determination result is output to the display unit 407 (step S27), the condition determination unit 52 determines whether the one or the other thin film is to be output. The value of the film thickness L1 or L2 and the value of the lattice constant a1 or a2 of the one or the other thin film are shown in a contour diagram like the lattice constant and film thickness illustrated in FIG. As points on the distribution map, they are stored in the auxiliary storage device 405 (step S29), and a distribution map indicating the degree of coincidence between the analysis profile and the actual measurement profile can be created later based on the accumulation of the stored information. deep.

  Then, it is checked whether or not an operation input for instructing creation of a distribution map has been made (step S30), and when instructed, the distribution map is displayed based on the data of the degree of coincidence stored and stored in the auxiliary storage device 405. A matching region 101 having the highest matching degree between the analysis profile and the actual measurement profile and at least one ring distributed so as to surround the matching region 101 is lower than the matching region 101 on the distribution map created. The distribution areas 102 to 104 are displayed in the visually distinguishable display manner as described above, and the points on the coincidence distribution map indicate which of the coincidence area 101 and the circular distribution areas 102 to 104 on the distribution map. The degree of coincidence can be visually identified by belonging to a region (step S32).

  Further, it is checked whether or not an operation input for instructing the end of measurement has been made. If instructed, the process is terminated (step S33). If there is no end instruction, the process returns to step S11 and waits for the start of the next measurement.

  As described above, in the diffraction X-ray measurement analysis method and program of the present embodiment, the period L of the superlattice structure and the average lattice constant a of the superlattice structure are obtained from the measured profile, and these values and known information are used. Based on these values, the initial values of the film thickness L1 and the lattice constant a1 of one of the first and second composition thin films are set as the initial values of two of the four variables. When the two variables are calculated, an analysis profile is created by theoretical calculation based on the information obtained so far, the analysis profile is compared with the actual measurement profile, and the degree of coincidence is determined according to the comparison result. When the coincidence criterion is satisfied, the four variables at that time are measured values, and when the criterion is not satisfied, one of the initial values that are two variables is changed and the variable calculation step is performed again. Back. Therefore, it is possible to quickly execute appropriate two initial value settings and a fitting process for changing either one or both of these set values in terms of convergence calculation, and to ensure required measurement accuracy. .

  In the present embodiment, in the setting stage, the main satellite peak is identified by extracting a periodic isolated peak from the measured profile based on the design value information related to the stacked superlattice structure. The adverse effect of the microscopic profile portion such as noise can be avoided more effectively, and the processing can be simplified.

  In addition, based on the period L and the average lattice constant a of the superlattice structure obtained from the measured profile and the design value information of the film thicknesses L1 and L2 and the lattice constants a1 and a2 of the one and the other thin films obtained from the measured profile in the setting stage. Thus, since the initial values of the film thickness L1 and the lattice constant a1 of the one thin film are set, an initial value closer to the measured value to be obtained can be set based on information obtained from the actual measurement profile, design information, and the like.

  In the present embodiment, in the comparison stage, the analysis profiles of the zero-order satellite peak P20 corresponding to the average lattice constant a of the superlattice structure among the plurality of satellite peaks are measured in the vertical axis direction and the horizontal axis direction, respectively. In accordance with the profile, the degree of coincidence between the analysis profile and the actual measurement profile of the satellite peak P21 of other orders among the main satellite peaks is examined. The degree comparison process can be simplified.

  Further, in the determination stage, when one of the setting values of the film thickness L1 and the lattice constant a1 of one thin film is changed and the process returns to the variable calculation stage again, the one thin film is made constant while keeping the period L of the superlattice structure constant. Since the set value of the film thickness L1 is finely adjusted, the convergence to the coincidence point can be accelerated by fixing the period L accurately obtained from the actual measurement profile.

  Furthermore, when changing one of the set values of the thin film thickness L1 and the lattice constant a1 and returning to the variable calculation stage again, the set value of the film thickness L1 is set while keeping the period L of the superlattice structure constant. Prior to the fine adjustment, the lattice constant a1 of the one thin film is finely adjusted, so that the convergence to the coincidence point can be accelerated considering the correlation in the change of the film thickness L1 and the lattice constant a1.

  In the present embodiment, in the determination step, the film thickness value L1 or L2 of one or the other thin film, the lattice constant value a1 or a2 of the one or the other thin film, the lattice constant and the film thickness are plotted on the vertical axis. And stored as points on a contour map like the contour map on the horizontal axis, creating a distribution map showing the degree of coincidence between the analysis profile and the actual measurement profile based on the stored information, and on the distribution map, The discriminating region 101 having the highest degree of coincidence between the analysis profile and the actual measurement profile is visually distinguished from the annular distribution regions 102 to 104 that are lower than the coincidence region 101 and are distributed so as to surround the coincidence region 101. The degree of coincidence depending on which region of the distribution map the points on the distribution map belong to among the matching region 101 and the circular distribution regions 102 to 104 displayed in the display mode Since visually identifiably indicated, it will be seen readily how much the degree of matching of the analysis profile and the measured profile, allowing the user quick and accurate global judgment.

  In the above-described embodiment, the active layer of a high-power semiconductor laser used in the communication field is taken as an example of a crystal structure having a superlattice structure in which different types of thin films are alternately stacked. Needless to say, the present invention can also be applied to other superlattice structures in which different types of thin films are alternately stacked.

  As described above, the present invention does not use a small peak or noise between satellite peaks for fitting, but sets appropriate two variables for a specific satellite peak selected based on known information and measured data. Since the fitting process that only changes the value setting and one or both of these initial values is performed quickly in terms of convergent calculation, quick and effective fitting is necessary for the main satellite peak reflecting the superlattice structure. An X-ray diffraction measurement analysis method and program capable of performing analysis with sufficient accuracy can be realized, and further, an X-ray diffraction measurement analysis method and program capable of making a global judgment by displaying the distribution of coincidence can be realized. Measurement of a superlattice structure in which different types of thin films are stacked alternately It is useful for X-ray diffraction measurement analysis method and program as a whole is used in the analysis.

It is a schematic block diagram of the measurement system of the apparatus which implements the diffraction X-ray measurement analysis method which concerns on the 1st Embodiment of this invention. 1 is an overall schematic configuration diagram of an apparatus that performs a diffraction X-ray measurement analysis method according to a first embodiment of the present invention. It is a principal part functional block diagram of the control apparatus of the apparatus which implements the diffraction X-ray measurement analysis method which concerns on the 1st Embodiment of this invention. FIG. 5 is a profile diagram of a diffracted X-ray illustrating an example of an analysis / measurement profile created by the diffracted X-ray measurement and analysis method according to the first embodiment of the present invention, where the vertical axis indicates the diffracted X-ray intensity and the horizontal axis indicates Each diffraction angle is shown. FIG. 5 is a coincidence distribution diagram of analysis / measurement profiles created by the diffraction X-ray measurement analysis method according to the first embodiment of the present invention, where the vertical axis represents the lattice constant of one or the other thin film, and the horizontal axis represents the thin film The film thickness is as follows. FIG. 5 is a coincidence distribution diagram of different modes of analysis / measurement profiles created by the diffraction X-ray measurement analysis method according to the first embodiment of the present invention, where the vertical axis represents the lattice constant of one or the other thin film, and the horizontal axis Is the thickness of the thin film. It is a flowchart which shows the general | schematic flow of the X-ray-diffraction measurement analysis program which concerns on the 1st Embodiment of this invention. It is explanatory drawing explaining the relationship between the parameter change performed with the diffraction X-ray measurement analysis method which concerns on the 1st Embodiment of this invention, and the change of an analysis profile by it. It is explanatory drawing explaining the fitting process performed with the diffraction X-ray measurement analysis method which concerns on the 1st Embodiment of this invention, and the state by which an analysis profile approaches an actual measurement profile by it.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st turntable 2 2nd turntable 3, 4 Drive means 6, 7 Rotation position detector 10 Sample substrate (substrate)
20 X-ray source 21 X-ray tube 22 Curved mirror 23 Monochromator 30 X-ray counter 40 Measurement analysis control device (distribution map creation means, output means)
41 Measured data storage unit (measured data storage means)
42 Measurement profile creation unit (measurement profile creation means)
43 Design information storage unit (design information storage means)
45 specific peak selection unit 46 peak specific condition storage unit (specific condition storage means)
47 Period / average lattice constant calculation unit (period calculation means, average lattice constant calculation means)
48 variable calculation unit (variable calculation means)
49 Analysis profile creation unit (analysis profile creation means)
51 Comparison unit (simulation processing unit, error analysis unit)
52 Condition determination unit (determination means, simulation processing unit)
101 Matching areas 102, 103, 104 Annular distribution area 401 CPU
402 ROM
403 RAM
404 I / O interface circuit 405 Auxiliary storage device (distributed data storage means)
406 Setting / input unit 407 Display unit (output means)

Claims (16)

X-ray diffraction obtained by detecting X-rays incident on a crystal structure having a superlattice structure in which a plurality of first composition thin films and a plurality of second composition thin films are alternately laminated on a substrate Based on the measurement information, the horizontal axis represents the X-ray diffraction angle, the vertical axis represents the X-ray diffraction intensity, and a plurality of substrate peaks derived from the diffracted X-rays from the substrate and the stacked superlattice structures A measured profile with satellite peaks;
According to the theoretical calculation of the X-ray diffraction phenomenon using the lattice constant and film thickness of the first composition thin film and the lattice constant and film thickness of the second composition thin film as four variables, the horizontal axis represents the X-ray diffraction angle and the vertical axis represents An analysis profile expressed as X-ray diffraction intensity,
Compare the four variables while changing them,
X-ray diffraction measurement analysis in which the four variables of the analysis profile in the best match state are the measured values of the lattice constant and film thickness of the first composition thin film and the lattice constant and film thickness of the second composition thin film, respectively. In the method
The period (L) of the superlattice structure is obtained from the interval between a plurality of main satellite peaks in the measured profile, and the satellite peak corresponding to the average composition of the superlattice structure in the measured profile and the substrate peak The average lattice constant (a) of the superlattice structure is obtained from the distance between the first composition thin film and the first composition thin film or the second composition thin film among the four variables. A setting step of setting an initial value of the lattice constant (a1) of one of the composition thin film or the second composition thin film;
From the period of the superlattice structure, the average lattice constant of the superlattice structure, the film thickness of the one thin film, and the set value of the lattice constant, the other of the film thicknesses of the first composition thin film or the second composition thin film A variable calculation stage for calculating values of the film thickness (L2) and the lattice constant (a2) of the thin film;
The theoretical calculation based on the period of the superlattice structure, the average lattice constant of the superlattice structure, the set value of the film thickness and lattice constant of the one thin film, and the calculated value of the film thickness and lattice constant of the other thin film An analysis profile creating step for obtaining the analysis profile by:
A comparison step of comparing the analysis profile and the actual measurement profile to check the degree of matching between the two profiles;
It is determined whether or not the degree of coincidence satisfies a predetermined coincidence criterion. When the degree of coincidence satisfies a predetermined coincidence criterion, the film thickness and lattice constant of the one thin film at that time When the initial value and the film thickness and lattice constant value of the other thin film are used as the film thickness measurement value and the lattice constant measurement value, and the degree of coincidence does not satisfy a predetermined coincidence criterion, the film of the one thin film An X-ray diffraction measurement analysis method comprising: a determination step of changing any set value of the thickness and the lattice constant and returning to the variable calculation step again.   The main satellite peak is identified by extracting an isolated peak having periodicity from the measured profile based on design value information regarding the stacked superlattice structure in the setting step. The X-ray diffraction measurement analysis method described.   In the setting step, the period and average lattice constant of the superlattice structure obtained from the actual measurement profile, and design value information of the film thicknesses (L1, L2) and lattice constants (a1, a2) of the one and the other thin films, 2. The X-ray diffraction measurement analysis method according to claim 1, wherein an initial value of a film thickness and a lattice constant of the one thin film is set based on the above.   In the comparison step, for the zero-order satellite peak corresponding to the average lattice constant of the superlattice structure among the plurality of satellite peaks, the analysis profile is adjusted to the actual measurement profile in the vertical axis direction and the horizontal axis direction, The X-ray diffraction measurement analysis according to any one of claims 1 to 3, wherein a degree of coincidence between the analysis profile and the actual measurement profile is examined for satellite peaks of other orders among the main satellite peaks. Method.   In the determination step, when changing one of the setting values of the film thickness and the lattice constant of the one thin film and returning to the variable calculation step again, the film of the one thin film is made constant while keeping the period of the superlattice structure constant. The X-ray diffraction measurement analysis method according to claim 1, wherein the set value of the thickness is finely adjusted.   When changing one of the setting values of the thin film thickness and the lattice constant and returning to the variable calculation stage again, the setting value of the film thickness of the one thin film is set while keeping the period of the superlattice structure constant. 6. The X-ray diffraction measurement analysis method according to claim 5, wherein a fine-tuning is performed on the lattice constant of the one thin film prior to fine-tuning. In the determination step, the film thickness (L1 or L2) of the one or other thin film and the value of the lattice constant (a1 or a2) of the one or other thin film, the lattice constant and the film thickness are represented by the vertical axis and the horizontal axis. And stored as points on the distribution map of the contour map and creating a distribution map showing the degree of coincidence between the analysis profile and the actual measurement profile based on the stored information,
On the distribution map, a matching region having the highest matching degree between the analysis profile and the actually measured profile, and at least one annular distribution region distributed so as to surround the matching region with the matching degree being lower than the matching region. Are displayed in a visually distinguishable display manner,
The degree of coincidence is displayed so as to be visually identifiable according to which of the coincidence area and the annular distribution area the points on the distribution map belong to. 6. The X-ray diffraction measurement analysis method according to any one of 6 above. X-ray diffraction obtained by detecting X-rays incident on a crystal structure having a superlattice structure in which a plurality of first composition thin films and a plurality of second composition thin films are alternately laminated on a substrate Based on the measurement information, the horizontal axis represents the X-ray diffraction angle, the vertical axis represents the X-ray diffraction intensity, and a plurality of substrate peaks derived from the diffracted X-rays from the substrate and the stacked superlattice structures A measured profile with satellite peaks;
According to the theoretical calculation of the X-ray diffraction phenomenon using the lattice constant and film thickness of the first composition thin film and the lattice constant and film thickness of the second composition thin film as four variables, the horizontal axis represents the X-ray diffraction angle and the vertical axis represents An analysis profile expressed as X-ray diffraction intensity,
Compare the four variables while changing them,
X-ray diffraction measurement analysis in which the four variables of the analysis profile in the best match state are the measured values of the lattice constant and film thickness of the first composition thin film and the lattice constant and film thickness of the second composition thin film, respectively. A program,
By computer
Period calculation means (47) for determining the period of the superlattice structure from the interval between a plurality of main satellite peaks in the actual measurement profile;
An average lattice constant calculating means (47) for obtaining an average lattice constant of the superlattice structure from an interval between the satellite peak corresponding to the average composition of the superlattice structure in the measured profile and the substrate peak;
The initial value of the film thickness of one thin film of the first composition thin film or the second composition thin film and the lattice constant of one thin film of the first composition thin film or the second composition thin film among the four variables is set. Initial value setting means (44) to perform,
From the period of the superlattice structure, the average lattice constant of the superlattice structure, the film thickness of the one thin film, and the set value of the lattice constant, the other of the film thicknesses of the first composition thin film or the second composition thin film Variable calculating means (48) for calculating the thickness of the thin film and the value of the lattice constant,
The theoretical calculation based on the period of the superlattice structure, the average lattice constant of the superlattice structure, the set value of the film thickness and lattice constant of the one thin film, and the calculated value of the film thickness and lattice constant of the other thin film An analysis profile creation means (49) for creating the analysis profile by:
Comparison means (51) for comparing the analysis profile and the actual measurement profile to check the degree of coincidence of both profiles;
It is determined whether or not the degree of coincidence satisfies a predetermined coincidence criterion. When the degree of coincidence satisfies a predetermined coincidence criterion, the film thickness (L1) of the one thin film at that time and When the set value of the lattice constant and the value of the other thin film and the value of the lattice constant are the film thickness measured value and the lattice constant measured value, and the degree of coincidence does not satisfy a predetermined coincidence criterion, X-ray diffraction measurement analysis characterized by realizing the function of a determination means (52) for changing any set value of the film thickness and lattice constant of the thin film and causing the variable calculation means to execute the calculation again. program.   The initial value setting means specifies a plurality of isolated peak generation regions having periodicity corresponding to the period of the superlattice structure in the measured profile based on design value information regarding the stacked superlattice structure. 9. The X-ray diffraction measurement analysis program according to claim 8, further comprising: a specific condition storage unit that stores conditions, and specifying the main satellite peak based on information stored in the specific condition storage unit.   The initial value setting means determines the period and average lattice constant of the superlattice structure obtained from the actual measurement profile, and the design values of the film thicknesses (L1, L2) and lattice constants (a1, a2) of the one and the other thin films. The X-ray diffraction measurement analysis program according to claim 8 or 9, wherein an initial value of a film thickness and a lattice constant of the one thin film is set based on the information.   Simulation for matching the analysis profile with the actual measurement profile in the vertical axis direction and the horizontal axis direction for the zero-order satellite peak corresponding to the average lattice constant of the superlattice structure among the plurality of satellite peaks. A simulation processing unit (51, 52) for executing the above and an error analysis unit (51) for checking the degree of coincidence between the analysis profile and the actual measurement profile for satellite peaks of other orders among the main satellite peaks The X-ray diffraction measurement analysis program according to any one of claims 8 to 10.   When the determination unit changes any set value of the film thickness and the lattice constant of the one thin film and causes the variable calculation unit to execute the calculation again, the initial value setting unit performs the period of the superlattice structure. The X-ray diffraction measurement analysis program according to any one of claims 8 to 11, wherein the set value of the film thickness of the one thin film is finely adjusted while maintaining a constant value.   When the determination unit changes any set value of the film thickness and the lattice constant of the one thin film and causes the variable calculation unit to execute the calculation again, the initial value setting unit performs the period of the superlattice structure. 13. The X-ray diffraction measurement analysis program according to claim 12, wherein the set value of the thickness of the one thin film is finely adjusted while the lattice constant of the one thin film is finely adjusted. In the computer,
Contour plots with the film thickness (L1 or L2) of the one or other thin film and the value of the lattice constant (a1 or a2) of the one or other thin film as the vertical and horizontal axes. Distribution data storage means (405) for storing as points on the distribution map of
A distribution diagram creating means (40) for generating distribution image information of the degree of coincidence between the analysis profile and the actual measurement profile based on the storage information of the distribution data storage means;
The X-ray diffraction measurement analysis program according to any one of claims 8 to 13, which realizes the function of output means for outputting distribution image information generated by the distribution map creation means.   Based on the storage information of the distribution data storage means, the distribution map creating means has a matching area having the highest degree of matching between the analysis profile and the measured profile, and the matching degree is lower than the matching area. 15. The X-ray diffraction measurement analysis program according to claim 14, wherein the display image information is visually distinguishable from at least one annular distribution region distributed so as to surround the region. A profile is displayed based on measurement information when X-rays are incident at different angles on a crystal structure having a superlattice structure in which a plurality of first composition thin films and a plurality of second composition thin films are alternately stacked on a substrate; Measured profile of diffracted X-ray intensity that varies with angle,
The profile is displayed based on theoretical calculation using the lattice constant (a1) and film thickness (L1) of the first composition thin film and the lattice constant (a2) and film thickness (L2) of the second composition thin film as four variables. And an analysis profile of the diffracted X-ray intensity that changes according to the angle,
Compare the four variables of the analysis profile while changing them,
X-ray diffraction measurement analysis in which the four variables of the analysis profile in the best match state are the measured values of the lattice constant and film thickness of the first composition thin film and the lattice constant and film thickness of the second composition thin film, respectively. A program,
When n is a positive integer, n values of the angle (x ₁ , x ₂ ,... x _n ) and n measured values of diffraction X-ray intensity corresponding to the angle (g ₁ , g ₂ ,..., G _n ) are sequentially stored in the memory, and measured data storage means (41);
A measured profile creating means (42) for creating a measured profile of the diffracted X-ray intensity that changes in accordance with the angle based on the data stored in the memory in a predetermined profile display format capable of being displayed and output;
Period calculation means (47) for determining the period (L) of the superlattice structure from the interval between a plurality of main satellite peaks in the actual measurement profile;
The average lattice constant (a) of the superlattice structure from the interval between the satellite peak that appears in the measured profile corresponding to the average composition of the superlattice structure and the substrate peak that appears in the measured profile due to the substrate. Means for calculating an average lattice constant (47),
The film thickness (L1 or L2) of one thin film of the first composition thin film or the second composition thin film and the lattice constant (a1 or a2) of one thin film of the first composition thin film or the second composition thin film. Initial value setting means (44) for setting initial values as initial values of two of the four variables (a1, L1, a2, L2);
From the period (L) of the superlattice structure, the average lattice constant (a) of the superlattice structure, and the set values of the film thickness (L1) and the lattice constant (a1) of the one thin film, the four variables Of the remaining two variables (a1, L1, a2, L2), the film thickness of the other thin film (L2) and the lattice constant (a2) of the film thickness of the first composition thin film or the second composition thin film Variable calculation means (48) for calculating values respectively;
The set values of the film thickness (L1) and the lattice constant (a1) of the one thin film, and the values of the film thickness (L2) and the lattice constant (a2) of the other thin film calculated by the variable calculation means (48). As the four variables, m angle values (x _i , x) that are positive integers less than n that specify an angle range corresponding to a specific satellite peak of a different order among the plurality of satellite peaks. _{j, ··· x i + m-} 1; however, i, j for m a positive integer smaller than) respectively, the values of the diffracted X-ray intensity _{(f i,} f j, the ··· _{f i + m-1)} Analysis profile creation means (49) for creating the analysis profile calculated by the theoretical calculation;
Comparison means (51) for comparing the analysis profile and the actual measurement profile with respect to a specific satellite peak having a different order among the plurality of satellite peaks, and checking the degree of coincidence of both profiles;
It is determined whether or not the degree of coincidence satisfies a predetermined coincidence criterion. When the degree of coincidence satisfies a predetermined coincidence criterion, the four variables (a1, L1) of the analysis profile at that time , A2, L2) are output as measured values of the film thickness and lattice constant of the one thin film and the film thickness and lattice constant of the other thin film, and the degree of coincidence does not satisfy a predetermined coincidence criterion The computer has the function of a determination means (52) for changing the set value of either the film thickness (L1) or the lattice constant (a1) of the one thin film and causing the variable calculation means to execute the calculation again. An X-ray diffraction measurement analysis program characterized by being used.