CN-121992366-A - MPCVD diamond growth temperature on-line monitoring method and system

CN121992366ACN 121992366 ACN121992366 ACN 121992366ACN-121992366-A

Abstract

The application discloses an MPCVD diamond growth temperature on-line monitoring method and system, and relates to the field of diamond growth technology, wherein the method comprises a plurality of optical sensing units, a time sequence-wave band control unit and an image acquisition wave band control unit, wherein the optical sensing units are circumferentially distributed on the inner wall surface of a deposition chamber at equal intervals, the optical axes of the optical sensing units point to a deposition table in the deposition chamber, the time sequence-wave band control unit is arranged in an optical path of each optical sensing unit and is used for controlling the acquisition frequency of each optical sensing unit and adjusting the image acquisition wave band so that each optical sensing unit acquires a radiation image in a target wave band; and the data processing unit is configured to integrate the collected radiation images of the plurality of optical sensing units into a two-dimensional thermal radiation image covering the deposition table, process the two-dimensional thermal radiation image and output the temperature of the surface of each diamond seed crystal according to the spatial layout of each diamond seed crystal. The application carries out non-contact, full-field and high-precision temperature real-time monitoring on the surfaces of a plurality of diamond seed crystals on a deposition table under the background radiation of strong plasmas.

Inventors

WANG HAIJUN
ZHANG ZHENBANG
HU FUSHENG
ZHANG GUANQUN
LIU LI
LI AOXIANG
TAO JIAN
ZHANG JUNAN

Assignees

宁波晶钻科技股份有限公司

Dates

Publication Date: 20260508
Application Date: 20260206

Claims (9)

1. An MPCVD diamond growth temperature on-line monitoring system, wherein the system is integrated with an MPCVD deposition chamber, the system comprising: the optical sensing units are circumferentially and equidistantly distributed on the inner wall surface of the deposition chamber, the optical axis of the optical sensing units points to a deposition table in the deposition chamber, and the deposition table carries a plurality of diamond seed crystal heat radiation and plasma background radiation; The time sequence-wave band control unit is arranged in the light path of each optical sensing unit and is used for controlling the acquisition frequency of each optical sensing unit and adjusting an image acquisition wave band so that each optical sensing unit acquires a radiation image under a target wave band, wherein the radiation image comprises a plurality of diamond seed crystal thermal radiation and plasma background radiation; The data processing unit is configured to receive the radiation images acquired by each optical sensing unit, integrate the radiation images acquired by the plurality of optical sensing units into a two-dimensional thermal radiation image covering the deposition table, process the two-dimensional thermal radiation image to obtain a two-dimensional temperature field of the surfaces of the plurality of diamond seed crystals on the deposition table, and output the temperature of the surfaces of each diamond seed crystal according to the spatial layout of each diamond seed crystal.
2. The MPCVD diamond growth temperature online monitoring system of claim 1, wherein the timing-band control unit comprises a timing control subunit and a band control subunit; The time sequence control subunit is electrically connected with the wave band control subunit; The timing control subunit is configured to receive the synchronous signal and generate a timing control instruction; The time sequence control subunit is configured to respond to the time sequence control instruction and adjust the acquisition frequency of each optical sensing unit; The band control subunit comprises a plurality of runner wheels, a plurality of optical filters, a plurality of optical sensing units and a plurality of control units, wherein the plurality of runner wheels are circumferentially and equidistantly arranged with each other, and the filtering band of each optical filter in the plurality of optical filters is different; the band control subunit is configured to, in response to the timing control instruction, rotate each runner body, and switch the optical filter passing through the optical path of the corresponding optical sensing unit.
3. The MPCVD diamond growth temperature online monitoring system according to claim 1, further comprising a plurality of protection devices and a plurality of optical windows, wherein the plurality of protection devices, the plurality of optical windows and the plurality of optical sensing units are in one-to-one correspondence; the plurality of protection devices are arranged on the inner wall of the deposition chamber, and each protection device is close to a corresponding optical window arranged on the inner wall of the deposition chamber; the optical window is configured to permit an optical axis of a corresponding optical sensing unit to pass through; each protection device comprises an air curtain protection device and/or a cooling device.
4. An MPCVD diamond growth temperature online monitoring method is applied to the MPCVD diamond growth temperature online monitoring system according to any one of claims 1 to 3, and is characterized in that the method executes a measurement flow according to measurement periods in an online measurement stage and comprises a first sampling node and a second sampling node in each measurement period; Under the first sampling node, the time sequence-wave band control unit enables each optical sensing unit to acquire a first radiation image under a first wave band, and under the second sampling node, the time sequence-wave band control unit enables each optical sensing unit to acquire a second radiation image under a second wave band; the data processing unit integrates the first radiation image acquired by each optical sensing unit in a first wave band to obtain a first full-coverage radiation image in the first wave band, and integrates the second radiation image acquired by each optical sensing unit in a second wave band to obtain a second full-coverage radiation image in the second wave band; S1, obtaining a first radiation response fitting coefficient and a first apparent emissivity corresponding to the first sampling node and a second radiation response fitting coefficient and a second apparent emissivity corresponding to the second sampling node in a current sampling period by using off-line calibration; s2, executing the following operations on the first full-coverage radiation image and the second full-coverage radiation image acquired in the current sampling period: Converting the first full-coverage radiation image into a first radiation brightness image by utilizing the first radiation response fitting coefficient, and converting the second full-coverage radiation image into a second radiation brightness image by utilizing the second radiation response fitting coefficient; based on the first radiation brightness image and the first apparent emissivity, and combining the second radiation brightness image and the second apparent emissivity, obtaining first real radiation brightness of the surfaces of the diamond seed crystals and second real radiation brightness of the surfaces of the diamond seed crystals; S3, based on the first real radiation brightness and the second real radiation brightness, inverting and calculating the temperature values of the surfaces of the plurality of diamond seed crystals according to the Planckian blackbody radiation law, and reconstructing the two-dimensional temperature field distribution of the surfaces of the plurality of diamond seed crystals; S4, determining the occupied area of each diamond seed crystal in a world coordinate system according to the spatial layout of each diamond seed crystal, and outputting the temperature of each diamond seed crystal surface through coordinate mapping based on the two-dimensional temperature field distribution of the surfaces of the plurality of diamond seed crystals.
5. The MPCVD diamond growth temperature online monitoring method of claim 4, wherein in the step of S1, using offline calibration, in a current sampling period, the first radiation response fitting coefficient and the first apparent emissivity corresponding to the first sampling node, and the second radiation response fitting coefficient and the second apparent emissivity corresponding to the second sampling node are obtained by: s1-11, placing a standard surface source black body at a position of a deposition table, and executing the following steps at any known temperature point: S1-111, controlling each optical sensing unit to collect a radiation image of the blackbody under a target wave band by the time sequence-wave band control unit, and integrating the radiation image into a full-coverage radiation image, wherein the target wave band is any wave band in the image collection wave band; s1-112, calculating the reference spectrum radiation brightness of the blackbody at the target wave band at the known temperature point according to the Planckian law; s1-113, executing the following steps aiming at a first target pixel in a full-coverage radiation image under a target wave band: the original digital gray value of the first target pixel is acquired, wherein the first target pixel is any pixel in the full-coverage radiation image under the target wave band; Performing nonlinear least square fitting on the original digital gray value of the first target pixel and the reference spectrum radiation brightness of the target wave band to obtain a radiation response fitting coefficient of the first target pixel under the target wave band; s1-12, establishing a radiation response fitting coefficient library according to the radiation response fitting coefficient of each pixel in the full-coverage radiation image under each wave band under a plurality of known temperature points; s1-13, determining a first radiation response fitting coefficient according to the first wave band based on the radiation response fitting coefficient library, and determining a second radiation response fitting coefficient according to the second wave band.
6. The MPCVD diamond growth temperature online monitoring method of claim 4, wherein in the step of S1, using offline calibration, in a current sampling period, the first radiation response fitting coefficient and the first apparent emissivity corresponding to the first sampling node, and the second radiation response fitting coefficient and the second apparent emissivity corresponding to the second sampling node are obtained by: s1-21, placing a diamond sample on a heating table with controllable temperature, and executing the following steps based on the surface state and the actual temperature of the diamond sample at the current moment: S1-211, controlling each optical sensing unit to collect a radiation image of the diamond sample under a target wave band by the time sequence-wave band control unit, and integrating the radiation image into a full-coverage radiation image, wherein the target wave band is any wave band in the image collection wave band; s1-212, converting the full-coverage radiation image under the target wave band into a radiation brightness image based on the radiation response fitting coefficient library; s1-213, calculating apparent emissivity of a second target pixel in the radiation brightness image according to kirchhoff radiation law based on apparent radiation brightness of the second target pixel in the radiation brightness image, wherein the second target pixel is any pixel in the radiation brightness image; S1-22, replacing diamond samples with different surface states and the actual temperatures of the diamond samples for multiple times, and accumulating apparent emissivity of each pixel in the radiation brightness images with different surface states and different temperatures to form an emissivity evaluation database; s1-23, determining a first apparent emissivity according to the first wave band and the surface state of the diamond seed crystal based on the emissivity evaluation database, and determining a second apparent emissivity according to the second wave band and the surface state of the diamond seed crystal.
7. The MPCVD diamond growth temperature on-line monitoring method of claim 6, wherein the apparent radiance of the ith row and jth column of pixels in the radiance image at the kth wavelength band is calculated using the formula: ; Wherein, the For the apparent radiance of the ith row, jth column of pixels in the radiance image at the kth band, For the kth band of wavelengths, For the full coverage of the original digital gray values of the ith row, jth column of picture elements in the radiation image at the kth band, And fitting coefficients for the radiation response of the pixels in the j th row and the j th column in the k th wave band.
8. The MPCVD diamond growth temperature on-line monitoring method of claim 4, wherein the first real radiance of the plurality of diamond seed surfaces and the second real radiance of the plurality of diamond seed surfaces are obtained using the following formula: ; Wherein, the Is the center wavelength of the first band of wavelengths, Is the center wavelength of the second band of wavelengths, To at the same time Apparent emissivity at To at the same time Apparent emissivity at Seed the diamond with a plurality of diamond The first real radiance below that is, Seed the diamond with a plurality of diamond A second true radiance below that of the first, Is the true temperature of the surfaces of a plurality of diamond seed crystals, For plasma in The first background radiation intensity below that is, For plasma in A second background radiation intensity below the first one, To at the same time The first radiation response fitting coefficient below, Is that The second radiation response fitting coefficient below, To at the same time Apparent radiance in the lower radiance image, To at the same time Apparent radiance in the lower radiance image, Is the proportionality coefficient of the background radiation spectrum type.
9. The MPCVD diamond growth temperature on-line monitoring method of claim 4, wherein the inversion calculation is performed using the following formula: ; Wherein, the Is the center wavelength of the first band of wavelengths, Is the center wavelength of the second band of wavelengths, To at the same time Apparent emissivity at To at the same time Apparent emissivity at Seed the diamond with a plurality of diamond The first real radiance below that is, Seed the diamond with a plurality of diamond A second real thermal radiation is then present, Is the true temperature of the surfaces of a plurality of diamond seed crystals, For the first radiation constant to be chosen, Is the second radiation constant.

Description

MPCVD diamond growth temperature on-line monitoring method and system Technical Field The application relates to the field of diamond growth technology, in particular to an on-line monitoring method and system for MPCVD diamond growth temperature. Background In the MPCVD diamond growth process, real-time and accurate monitoring of the surface temperature of a diamond seed crystal is a key for regulating and controlling growth dynamics and ensuring crystal quality. Currently, this field relies mainly on two types of technologies: First, single point infrared temperature measurement technology, in which a single point infrared thermometer is used to aim at individual diamond seed crystals for measurement through a chamber observation window. The method has the obvious defects that the temperature of discrete points can be obtained only, the full-field temperature distribution of the multi-diamond seed crystal on the deposition table can not be obtained, and therefore, the process uniformity can not be evaluated, meanwhile, the measuring signal is extremely easy to be interfered by intense plasma background radiation in the cavity, the measured temperature value is a mixed signal of target radiation and background radiation, the actual temperature of the surface of the diamond seed crystal is seriously deviated, and the measuring precision and reliability are low. And secondly, thermocouple contact measurement, namely embedding the thermocouple into a pedestal or contacting a sample for temperature measurement. The method has the greatest defects that the method belongs to invasive measurement, can interfere a local temperature field and an airflow field, cannot directly measure the real temperature of the diamond growth surface, and is not suitable for non-interfering in-situ on-line monitoring of the growth surface. Therefore, the related technology cannot realize non-contact, full-field and high-precision temperature on-line monitoring of the growth surfaces of a plurality of diamond seed crystals under the strong plasma interference environment of the MPCVD technology. Disclosure of Invention The application aims to provide an on-line monitoring method and an on-line monitoring system for MPCVD diamond growth temperature, which can carry out non-contact, full-field and high-precision temperature real-time monitoring on the surfaces of a plurality of diamond seed crystals on a deposition table under the background radiation of strong plasmas. In order to achieve the above object, the present application provides the following solutions: In a first aspect, the present application provides an MPCVD diamond growth temperature on-line monitoring system integrated with an MPCVD deposition chamber, the system comprising: the optical sensing units are circumferentially and equidistantly distributed on the inner wall surface of the deposition chamber, the optical axis of the optical sensing units points to a deposition table in the deposition chamber, and the deposition table carries a plurality of diamond seed crystal heat radiation and plasma background radiation; The time sequence-wave band control unit is arranged in the light path of each optical sensing unit and is used for controlling the acquisition frequency of each optical sensing unit and adjusting an image acquisition wave band so that each optical sensing unit acquires a radiation image under a target wave band, wherein the radiation image comprises a plurality of diamond seed crystal thermal radiation and plasma background radiation; The data processing unit is configured to receive the radiation images acquired by each optical sensing unit, integrate the radiation images acquired by the plurality of optical sensing units into a two-dimensional thermal radiation image covering the deposition table, process the two-dimensional thermal radiation image to obtain a two-dimensional temperature field of the surfaces of the plurality of diamond seed crystals on the deposition table, and output the temperature of the surfaces of each diamond seed crystal according to the spatial layout of each diamond seed crystal. Optionally, the timing-band control unit includes a timing control subunit and a band control subunit; The time sequence control subunit is electrically connected with the wave band control subunit; The timing control subunit is configured to receive the synchronous signal and generate a timing control instruction; The time sequence control subunit is configured to respond to the time sequence control instruction and adjust the acquisition frequency of each optical sensing unit; The band control subunit comprises a plurality of runner wheels, a plurality of optical filters, a plurality of optical sensing units and a plurality of control units, wherein the plurality of runner wheels are circumferentially and equidistantly arranged with each other, and the filtering band of each optical filter in the plurality of optical filters is different; the ban