Online real-time representation device for film epitaxial growth

Abstract

The invention discloses an online real-time representation device for film epitaxial growth. The online real-time representation device utilizes Raman spectroscopy signals to directly represent the microstructure of a nano material in MOCVD (Metal Organic Chemical Vapour Deposition) equipment in real time during a film epitaxial growth process. After reflected by a first spectroscope, excitation light is focused by a plane-convex lens, and the focus is radiated to an epitaxial wafer through an observing window in the top of the reaction cavity of the MOCVD equipment; since the Raman spectroscopy signals are excited in the radiation area of the focus of the plane-convex lens, most Raman spectroscopy signals are collected by the plane-convex lens; after passing through the first spectroscope, the Raman spectroscopy signals gather in the focus of the plane-convex lens, at the moment, a confocal pinhole is formed in the focus, and performs the function of space filtering and stray light resisting. The excitation light and the detection light (namely the Raman spectroscopy signals) share a light path front end unit, the size of a probe can be reduced as far as possible, and space limitation of the observing window of the reaction chamber is broken.

Description

technical field [0001] The invention belongs to the technical field of on-line monitoring, and more particularly relates to an on-line real-time characterization device for thin film epitaxial growth in MOCVD equipment. Background technique [0002] Metal Organic Chemical Vapour Deposition (MOCVD, Metal Organic Chemical Vapour Deposition) method is more and more widely used in the growth of nanomaterials due to its mature technology and good epitaxial growth quality, especially in the heteroepitaxial growth of GaN-based LEDs. Tool of. [0003] MOCVD is the use of metal organic compounds (MO) and hydrides, through chemical reactions such as cracking and synthesis in a high temperature reaction chamber, to perform thin film epitaxy growth on epitaxial wafers in the form of gas phase. [0004] As the structure of MOCVD epitaxial material growth becomes more and more complex, the components, atomic layer thickness and film quality that need to be controlled in the growth are ge...

AI Technical Summary

Problems solved by technology

[0005] However, due to the particularity of MOCVD technology, the application of various characterization techniques in online monitoring is greatly limited.

[0006] 1. The reaction environment is full of various components and various concentrations of reaction gases, which greatly limits the characterization techniques that work by emitting electrons, such as reflection high-energy electron diffraction (RHEED), scanning electron microscopy (SEM), etc.

[0007] 2. The limited space of the reaction chamber and the rapidly rotating substrate limit the X-ray diffraction (XRD) technology that works in the scanning mode of variable grazing angle or variable wavelength.

However, due to the information obtained indirectly, there must be large errors and uncertainties.

[0017] 4. Surface warpage of the epitaxial layer

[0019] Although the on-line measurement of the surface warpage of the epitaxial layer can reflect the stress formation and change process of the heteroepitaxial layer in real time, the root cause of the change of the warpage is the dislocation caused by the mismatch of the lattice constant and the thermal expansion coefficient. Warpage measurement belongs to the inference of microscopic characteristics from macroscopic phenomena, and there are also errors and uncertainties

[0020] To sum up, there is currently no technology or product that can directly characterize the microstructure, crystal state, doping composition and concentration of nanomaterials in MOCVD in real time.

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