Raman spectroscopy imaging is mainly used to obtain chemical information of substances and their spatial distribution. Millennial Raman Spectrometer greatly improves the quality and speed of Raman spectroscopy imaging through high spectral resolution and low stray light spectrometer, ensuring data accuracy and repeatability. The equipment supports HJT process, improves battery efficiency and passivation effect by optimizing process parameters, silicon thin film crystallization rate.

The impact of Raman spectroscopy imaging on improving imaging quality and speed

Raman spectroscopy is a non-destructive, label-free, highly sensitive means of characterizing chemical information of materials, while Raman imaging is a functional imaging technology for detecting the distribution state of chemical information in physical space.

When using Raman imaging technology to image samples, no additional preprocessing of the samples is required. The multi-dimensional high (hyper) spectral data set obtained by Raman imaging usually contains hundreds, thousands or even millions of independent Raman fingerprint spectra containing spatial position information. For simple single-layer samples, the data finally obtained by Raman imaging is three-dimensional, two-dimensional plane space plus the third-dimensional scattered light wavelength information, that is, spatial coordinate information plus material spectrum information. High-dimensional Raman imaging data is generally called Raman spectral data set.

Optical design of scanning Raman imaging system and schematic diagram of hyperspectral data set structure

Raman spectroscopy processing and analysis

Although Raman spectroscopy is closely related to the chemical properties of substances, highly sensitive Raman spectroscopy can be used to characterize the chemical information of substances, but in fact, the spectral characteristics of samples with similar chemical structures are very different, and different spectral analysis methods are required to distinguish these differences.

The main processes and methods for analyzing and processing Raman spectroscopy-related data. The pre-processing steps of Raman spectroscopy mainly include: removing spike noise, removing Gaussian thermal noise, spectral baseline correction, and spectral normalization. The univariate analysis of Raman spectroscopy means that the Raman spectrum contains the molecular fingerprint information of the sample, that is, each spectral characteristic peak in the Raman spectrum corresponds to a specific chemical group. The analysis method of extracting one or several layers representing chemical specificity from the Raman spectral data set to replace the chemical system contained in the huge spectral data set is the univariate analysis method.

Examples of processing and analysis of Raman spectroscopy and Raman imaging data

Raman Spectrometer can be used for both spectroscopy and imaging. Spectrometers with high spectral resolution and extremely low stray light ensure the accuracy and repeatability of spectral data, which can greatly improve the quality and speed of Raman spectral imaging and effectively extract spectral information.

The functions of HJT crystallization rate test are mainly reflected in:

Improving cell efficiency: Through crystallization, the band gap mismatch between amorphous silicon and single crystal silicon can be reduced, and the barrier height can be adjusted to help minority carriers transition smoothly.

Improving passivation effect: In HJT cell, the amorphous silicon layer has a good passivation effect, which can avoid direct contact between the electrode and the silicon substrate, thereby reducing interface recombination and surface recombination losses, and further improving cell performance.

Optimizing process parameters: Through the crystallization rate test, the dilution rate of silane and hydrogen can be accurately controlled to achieve a higher proportion of hydrogen, thereby improving the crystallization rate of silicon film. At the same time, the introduction of VHF power supply instead of traditional RF power supply helps to increase the deposition rate of microcrystalline film.

Raman Spectrometer

E-mail: market@millennialsolar.com

Millennial Raman Spectrometer has a powerful function to adapt to HJT crystallization rate testing. The equipment is independently developed and optimized for HJT process, and can support in-situ testing of process wafers to adapt to HJT development and production. It is equipped with fitting software that can calculate the crystallization rate while fitting the spectrum with one click, which is simple and intuitive.

UV sensitivity: The signal count of the first-order peak of silicon is better than 1000 (1 second integration time) Detection conditions

The quantum efficiency at 300 nm is higher than 60%, and the quantum efficiency at 700 nm is better than 58%

325 nm laser, laser power ≥12mW, low wave number to ≤150 cmm-1

Spectral repeatability: After single silicon calibration, ≤520±0.02cm-1

Raman spectroscopy imaging technology can non-destructively obtain the chemical and spatial information of substances. Millennial Raman Spectrometer improves imaging quality and speed through high spectral resolution and low stray light technology to ensure data accuracy and repeatability. This equipment supports HJT process, optimizes process parameters, improves cell efficiency and passivation effect, and is an important tool for HJT research and development and production.